Ch XIV

THE BLOOD VESSELS

Anatomy--INJURIES OF ARTERIES: _Varieties_--INJURIES OF VEINS: _Air Embolism_--Repair of blood vessels and natural arrest of hæmorrhage--HÆMORRHAGE: _Varieties_; _Prevention_; _Arrest_--Constitutional effects of hæmorrhage--Hæmophilia--DISEASES OF BLOOD VESSELS: Thrombosis; Embolism--Arteritis: _Varieties_; Arterio-sclerosis--Thrombo-phlebitis--Phlebitis: _Varieties_--VARIX--ANGIOMATA--Nævus: _Varieties_; _Electrolysis_--Cirsoid aneurysm--ANEURYSM: _Varieties_; _Methods of treatment_--ANEURYSMS OF INDIVIDUAL ARTERIES.

#Surgical Anatomy.#--An _artery_ has three coats: an internal coat--the _tunica intima_--made up of a single layer of endothelial cells lining the lumen; outside of this a layer of delicate connective tissue; and still farther out a dense tissue composed of longitudinally arranged elastic fibres--the internal elastic lamina. The tunica intima is easily ruptured. The middle coat, or _tunica media_, consists of non-striped muscular fibres, arranged for the most part concentrically round the vessel. In this coat also there is a considerable proportion of elastic tissue, especially in the larger vessels. The thickness of the vessel wall depends chiefly on the development of the muscular coat. The external coat, or _tunica externa_, is composed of fibrous tissue, containing, especially in vessels of medium calibre, some yellow elastic fibres in its deeper layers.

In most parts of the body the arteries lie in a sheath of connective tissue, from which fine fibrous processes pass to the tunica externa. The connection, however, is not a close one, and the artery when divided transversely is capable of retracting for a considerable distance within its sheath. In some of the larger arteries the sheath assumes the form of a definite membrane.

The arteries are nourished by small vessels--the _vasa vasorum_--which ramify chiefly in the outer coat. They are also well supplied with nerves, which regulate the size of the lumen by inducing contraction or relaxation of the muscular coat.

The _veins_ are constructed on the same general plan as the arteries, the individual coats, however, being thinner. The inner coat is less easily ruptured, and the middle coat contains a smaller proportion of muscular tissue. In one important point veins differ structurally from arteries--namely, in being provided with valves which prevent reflux of the blood. These valves are composed of semilunar folds of the tunica intima strengthened by an addition of connective tissue. Each valve usually consists of two semilunar flaps attached to opposite sides of the vessel wall, each flap having a small sinus on its cardiac side. The distension of these sinuses with blood closes the valve and prevents regurgitation. Valves are absent from the superior and inferior venæ cavæ, the portal vein and its tributaries, the hepatic, renal, uterine, and spermatic veins, and from the veins in the lower part of the rectum. They are ill-developed or absent also in the iliac and common femoral veins--a fact which has an important bearing on the production of varix in the veins of the lower extremity.

The wall of _capillaries_ consists of a single layer of endothelial cells.

HÆMORRHAGE

Various terms are employed in relation to hæmorrhage, according to its seat, its origin, the time at which it occurs, and other circumstances.

The term _external hæmorrhage_ is employed when the blood escapes on the surface; when the bleeding takes place into the tissues or into a cavity it is spoken of as _internal_. The blood may infiltrate the connective tissue, constituting an _extravasation_ of blood; or it may collect in a space or cavity and form a _hæmatoma_.

The coughing up of blood from the lungs is known as _hæmoptysis_; vomiting of blood from the stomach, as _hæmatemesis_; the passage of black-coloured stools due to the presence of blood altered by digestion, as _melæna_; and the passage of bloody urine, as _hæmaturia_.

Hæmorrhage is known as arterial, venous, or capillary, according to the nature of the vessel from which it takes place.

In _arterial_ hæmorrhage the blood is bright red in colour, and escapes from the cardiac end of the divided vessel in pulsating jets synchronously with the systole of the heart. In vascular parts--for example the face--both ends of a divided artery bleed freely. The blood flowing from an artery may be dark in colour if the respiration is impeded. When the heart's action is weak and the blood tension low the flow may appear to be continuous and not in jets. The blood from a divided artery at the bottom of a deep wound, escapes on the surface in a steady flow.

_Venous_ bleeding is not pulsatile, but occurs in a continuous stream, which, although both ends of the vessel may bleed, is more copious from the distal end. The blood is dark red under ordinary conditions, but may be purplish, or even black, if the respiration is interfered with. When one of the large veins in the neck is wounded, the effects of respiration produce a rise and fall in the stream which may resemble arterial pulsation.

In _capillary_ hæmorrhage, red blood escapes from numerous points on the surface of the wound in a steady ooze. This form of bleeding is serious in those who are the subjects of hæmophilia.

INJURIES OF ARTERIES

The following description of the injuries of arteries refers to the larger, named trunks. The injuries of smaller, unnamed vessels are included in the consideration of wounds and contusions.

#Contusion.#--An artery may be contused by a blow or crush, or by the oblique impact of a bullet. The bruising of the vessel wall, especially if it is diseased, may result in the formation of a thrombus which occludes the lumen temporarily or even permanently, and in rare cases may lead to gangrene of the limb beyond.

#Subcutaneous Rupture.#--An artery may be ruptured subcutaneously by a blow or crush, or by a displaced fragment of bone. This injury has been produced also during attempts to reduce dislocations, especially those of old standing at the shoulder. It is most liable to occur when the vessels are diseased. The rupture may be incomplete or complete.

_Incomplete Subcutaneous Rupture._--In the majority of cases the rupture is incomplete--the inner and middle coats being torn, while the outer remains intact. The middle coat contracts and retracts, and the internal, because of its elasticity, curls up in the interior of the vessel, forming a valvular obstruction to the blood-flow. In most cases this results in the formation of a thrombus which occludes the vessel. In some cases the blood-pressure gradually distends the injured segment of the vessel wall and leads to the formation of an aneurysm.

The pulsation in the vessels beyond the seat of rupture is arrested--for a time at least--owing to the occlusion of the vessel, and the limb becomes cold and powerless. The pulsation seldom returns within five or six weeks of the injury, if indeed it is not permanently arrested, but, as a rule, a collateral circulation is rapidly established, sufficient to nourish the parts beyond. If the pulsation returns within a week of the injury, the presumption is that the occlusion was due to pressure from without--for example, by hæmorrhage into the sheath or the pressure of a fragment of bone.

_Complete Subcutaneous Rupture._--When the rupture is complete, all the coats of the vessel are torn and the blood escapes into the surrounding tissues. If the original injury is attended with much shock, the bleeding may not take place until the period of reaction. Rupture of the popliteal artery in association with fracture of the femur, or of the axillary or brachial artery with fracture of the humerus or dislocation of the shoulder, are familiar examples of this injury.

Like incomplete rupture, this lesion is accompanied by loss of pulsation and power, and by coldness of the limb beyond; a tense and excessively painful swelling rapidly appears in the region of the injury, and, where the cellular tissue is loose, may attain a considerable size. The pressure of the effused blood occludes the veins and leads to congestion and œdema of the limb beyond. The interference with the circulation, and the damage to the tissues, may be so great that gangrene ensues.

_Treatment._--When an artery has been contused or ruptured, the limb must be placed in the most favourable condition for restoration of the circulation. The skin is disinfected and the limb wrapped in cotton wool to conserve its heat, and elevated to such an extent as to promote the venous return without at the same time interfering with the inflow of blood. A careful watch must be kept on the state of nutrition of the limb, lest gangrene occurs.

If no complications supervene, the swelling subsides, and recovery may be complete in six or eight weeks. If the extravasation is great and the skin threatens to give way, or if the vitality of the limb is seriously endangered, it is advisable to expose the injured vessel, and, after clearing away the clots, to attempt to suture the rent in the artery, or, if torn across, to join the ends after paring the bruised edges. If this is impracticable, a ligature is applied above and below the rupture. If gangrene ensues, amputation must be performed.

These descriptions apply to the larger arteries of the extremities. A good illustration of subcutaneous rupture of the arteries of the head is afforded by the tearing of the middle meningeal artery caused by the application of blunt violence to the skull; and of the arteries of the trunk--caused by the tearing of the renal artery in rupture of the kidney.

#Open Wounds of Arteries--Laceration.#--Laceration of large arteries is a common complication of machinery and railway accidents. The violence being usually of a tearing, twisting, or crushing nature, such injuries are seldom associated with much hæmorrhage, as torn or crushed vessels quickly become occluded by contraction and retraction of their coats and by the formation of a clot. A whole limb even may be avulsed from the body with comparatively little loss of blood. The risk in such cases is secondary hæmorrhage resulting from pyogenic infection.

The _treatment_ is that applicable to all wounds, with, in addition, the ligation of the lacerated vessels.

#Punctured wounds# of blood vessels may result from stabs, or they may be accidentally inflicted in the course of an operation.

The division of the coats of the vessel being incomplete, the natural hæmostasis that results from curling up of the intima and contraction of the media, fails to take place, and bleeding goes on into the surrounding tissues, and externally. If the sheath of the vessel is not widely damaged, the gradually increasing tension of the extravasated blood retained within it may ultimately arrest the hæmorrhage. A clot then forms between the lips of the wound in the vessel wall and projects for a short distance into the lumen, without, however, materially interfering with the flow through the vessel. The organisation of this clot results in the healing of the wound in the vessel wall.

In other cases the blood escapes beyond the sheath and collects in the surrounding tissues, and a traumatic aneurysm results. Secondary hæmorrhage may occur if the wound becomes infected.

The _treatment_ consists in enlarging the external wound to permit of the damaged vessel being ligated above and below the puncture. In some cases it may be possible to suture the opening in the vessel wall. When circumstances prevent these measures being taken, the bleeding may be arrested by making firm pressure over the wound with a pad; but this procedure is liable to be followed by the formation of an aneurysm.

_Minute puncture of arteries_ such as frequently occur in the hypodermic administration of drugs and in the use of exploring needles, are not attended with any escape of blood, chiefly because of the elastic recoil of the arterial wall; a tiny thrombus of platelets and thrombus forms at the point where the intima is punctured.

#Incised Wounds.#--We here refer only to such incised wounds as partly divide the vessel wall.

Longitudinal wounds show little tendency to gape, and are therefore not attended with much bleeding. They usually heal rapidly, but, like punctured wounds, are liable to be followed by the formation of an aneurysm.

When, however, the incision in the vessel wall is oblique or transverse, the retraction of the muscular coat causes the opening to gape, with the result that there is hæmorrhage, which, even in comparatively small arteries, may be so profuse as to prove dangerous. When the associated wound in the soft parts is valvular the hæmorrhage is arrested and an aneurysm may develop.

When a large arterial trunk, such as the external iliac, the femoral, the common carotid, the brachial, or the popliteal, has been partly divided, for example, in the course of an operation, the opening should be closed with sutures--_arteriorrhaphy_. The circulation being controlled by a tourniquet, or the artery itself occluded by a clamp, fine silk or catgut stitches are passed through the outer and middle coats after the method of Lembert, a fine, round needle being employed. The sheath of the vessel or an adjacent fascia should be stitched over the line of suture in the vessel wall. If infection be excluded, there is little risk of thrombosis or secondary hæmorrhage; and even if thrombosis should develop at the point of suture, the artery is obstructed gradually, and the establishment of a collateral circulation takes place better than after ligation. In the case of smaller trunks, or when suture is impracticable, the artery should be tied above and below the opening, and divided between the ligatures.

#Gunshot Wounds of Blood Vessels.#--In the majority of cases injuries of large vessels are associated with an external wound; the profusion of the bleeding indicates the size of the damaged vessel, and the colour of the blood and the nature of the flow denote whether an artery or a vein is implicated.

When an artery is wounded a firm _hæmatoma_ may form, with an expansile pulsation and a palpable thrill--whether such a hæmatoma remains circumscribed or becomes diffuse depends upon the density or laxity of the tissues around it. In course of time a _traumatic arterial aneurysm_ may develop from such a hæmatoma.

When an artery and its companion vein are injured simultaneously an _arterio-venous aneurysm_ (p. 310) may develop. This frequently takes place without the formation of a hæmatoma as the arterial blood finds its way into the vein and so does not escape into the tissues. Even if a hæmatoma forms it seldom assumes a great size. In time a swelling is recognised, with a palpable thrill and a systolic bruit, loudest at the level of the communication and accompanied by a continuous venous hum.

If leakage occurs into the tissues, the extravasated blood may occlude the vein by pressure, and the symptoms of arterial aneurysm replace those of the arterio-venous form, the systolic bruit persisting, while the venous hum disappears.

_Gangrene_ may ensue if the blood supply is seriously interfered with, or the signs of _ischæmia_ may develop; the muscles lose their elasticity, become hard and paralysed, and anæsthesia of the "glove" or "stocking" type, with other alterations of sensation ensue. Apart from ischæmia, _reflex paralysis_ of motion and sensation of a transient kind may follow injury of a large vessel.

_Treatment_ is carried out on the same lines as for similar injuries due to other causes.

INJURIES OF VEINS

Veins are subject to the same forms of injury as arteries, and the results are alike in both, such variations as occur being dependent partly on the difference in their anatomical structure, and partly on the conditions of the circulation through them.

#Subcutaneous rupture# of veins occur most frequently in association with fractures and in the reduction of dislocations. The veins most commonly ruptured are the popliteal, the axillary, the femoral, and the subclavian. On account of the smaller amount of elastic and muscular tissue in the wall of a vein, the contraction and retraction of its walls are less than in an artery, and so bleeding may continue for a longer period. On the other hand, owing to the lower blood-pressure the outflow goes on more slowly, and the gradually increasing pressure produced by the extravasated blood is usually sufficient to arrest the hæmorrhage before it becomes serious. As an aid in diagnosing the source of the bleeding, it should be remembered that the rupture of a vein does not affect the pulsation in the limb beyond. The risks are practically the same as when an artery is ruptured, excepting that of aneurysm, and the treatment is carried out on the same lines, but it is seldom necessary to operate for the purpose of applying a ligature to the injured vein.

#Wounds# of veins--punctured and incised--frequently occur in the course of operations; for example, in the removal of tumours or diseased glands from the neck, the axilla, or the groin. They are also met with as a result of accidental stabs and of suicidal or homicidal injuries. The hæmorrhage from a large vein so damaged is usually profuse, but it is more readily controlled by external pressure than that from an artery. When a vein is merely punctured, the bleeding may be arrested by pressure with a pad of gauze, or by a lateral ligature--that is, picking up the margins of the rent in the wall and securing them with a ligature without occluding the lumen. In the large veins, such as the internal jugular, the femoral, or the axillary, it is usually possible to suture the opening in the wall. This does not necessarily result in thrombosis in the vessel, or in obliteration of its lumen.

When an _artery and vein are simultaneously wounded_, the features peculiar to each are present in greater or less degree. In the limbs gangrene may ensue, especially if the wound is infected. Punctured and gun-shot wounds implicating both artery and vein are liable to be followed by the development of arterio-venous aneurysm.

#Entrance of Air into Veins--Air Embolism.#--This serious, though fortunately rare, accident is apt to occur in the course of operations in the region of the thorax, neck, or axilla, if a large vein is opened and fails to collapse on account of the rigidity of its walls, its incorporation in a dense fascia, or from traction being made upon it. If the wound in a vein is thus held open, the negative pressure during inspiration sucks air into the right side of the heart. This is accompanied by a hissing or gurgling sound, and with the next expiration some frothy blood escapes from the wound. The patient instantly becomes pale, the pupils dilate, respiration becomes laboured, and although the heart may continue to beat forcibly, the peripheral pulse is weak, and may even be imperceptible. On auscultating the heart, a churning sound may be heard. Death may result in a few minutes; or the heart may slowly regain its power and recovery take place.

_Prevention._--In operations in the "dangerous area"--as the region of the root of the neck is called in this connection--care must be taken not to cut or divide any vein before it has been secured by forceps, and to apply ligatures securely and at once. Deep wounds in this region should be kept filled with normal salt solution. Immediately a cut is recognised in a vein, a finger should be placed over the vessel on the cardiac side of the wound, and kept there until the opening is secured.

_Treatment._--Little can be done after the air has actually entered the vein beyond endeavouring to maintain the heart's action by hypodermic injections of ether or strychnin and the application of mustard or hot cloths over the chest. The head at the same time should be lowered to prevent syncope. Attempts to withdraw the air by suction, and the employment of artificial respiration, have proved futile, and are, by some, considered dangerous. In a desperate case massage of the heart might be tried.

THE NATURAL ARREST OF HÆMORRHAGE AND THE REPAIR OF BLOOD VESSELS

#Primary Hæmorrhage.#--The term primary hæmorrhage is applied to the bleeding which follows immediately on the wounding of a blood vessel. The natural process by which such hæmorrhage is arrested varies with the character of the wound in the vessel and may be modified by accidental circumstances.

(a) _Repair of completely divided Artery._--When an artery is _completely_ divided, the circular fibres of the muscular coat contract, so that the lumen of the cut ends is diminished, and at the same time each segment retracts within its sheath in virtue of the recoil of the elastic elements in its walls, the tunica intima curls up in the interior of the vessel, and the tunica externa collapses over the cut ends. The blood that escapes from the injured vessel fills the interstices of the tissues, and, coagulating, forms a clot which temporarily arrests the bleeding. That part of the clot which lies between the divided ends of the vessel and in the cellular tissue outside, is known as the _external clot_, while the portion which projects into the lumen of the vessel is known as the _internal clot_, and it usually extends as far as the nearest collateral branch. These processes constitute what is known as the _temporary arrest of hæmorrhage_, which, it will be observed, is effected by the contraction and retraction of the divided artery and by clotting.

The _permanent arrest_ takes place by the transformation of the clot into scar tissue. The internal clot plays the most important part in the process; it becomes invaded by leucocytes and proliferating endothelial and connective-tissue cells, and new blood vessels permeate the mass, which is thus converted into granulation tissue. This is ultimately replaced by fibrous tissue, which permanently occludes the end of the vessel. Concurrently and by the same process the external clot is converted into scar tissue.

If a divided artery is _ligated at its cut end_, the tension of the ligature is usually sufficient to rupture the inner and middle coats, which curl up within the lumen, the outer coat alone being held in the grasp of the ligature. An internal clot forms and, becoming organised, permanently occludes the vessel as above described. The ligature and the small portion of vessel beyond it are subsequently absorbed.

In course of time the collateral branches of the vessel above and below the level of section enlarge and their inter-communication becomes more free, so that even when large trunks have been divided the vascular supply of the parts beyond may be completely restored. This is known as the development of the _collateral circulation_.

_Imperfect Collateral Circulation._--While the development of the collateral circulation after the ligation or obstruction from other cause of a main arterial trunk may be sufficient to prevent gangrene of the limb, it may be insufficient for its adequate nourishment; it may be cold, bluish in colour, and there may be necrosis of the skin over bony points; this is notably the case in the lower extremity after ligation of the femoral or popliteal artery, when patches of skin may die over the prominence of the heel, the balls of the toes, the projecting base of the fifth metatarsal and the external malleolus.

If, during the period of reaction, the blood-pressure rises considerably, the occluding clot at the divided end of the vessel may be washed away or the ligature displaced, permitting of fresh bleeding taking place--_reactionary_ or _intermediary hæmorrhage_ (p. 272).

In the event of the wound becoming infected with pyogenic organisms, the occluding blood-clot or the young fibrous tissue may become disintegrated in the suppurative process, and the bleeding start afresh--_secondary hæmorrhage_ (p. 273).

(b) If an artery is only _partly cut across_, the divided fibres of the tunica muscularis contract and those of the tunica externa retract, with the result that a more or less circular hole is formed in the wall of the vessel, from which free bleeding takes place, as the conditions are unfavourable for the formation of an occluding clot. Even if a clot does form, when the blood-pressure rises it is readily displaced, leading to reactionary hæmorrhage. Should the wound become infected, secondary hæmorrhage is specially liable to occur. A further risk attends this form of injury, in that the intra-vascular tension may in time lead to gradual stretching of the scar tissue which closes the gap in the vessel wall, with the result that a localised dilatation or diverticulum forms, constituting a _traumatic aneurysm_.

(c) When the injury merely takes the form of a _puncture_ or _small incision_ a blood-clot forms between the edges, becomes organised, and is converted into cicatricial tissue which seals the aperture. Such wounds may also be followed by reactionary or secondary hæmorrhage, or later by the formation of a traumatic aneurysm.

_Conditions which influence the Natural Arrest of Hæmorrhage._--The natural arrest of bleeding is favoured by tearing or crushing of the vessel walls, owing to the contraction and retraction of the coats and the tendency of blood to coagulate when in contact with damaged tissue. Hence the primary hæmorrhage following lacerated wounds is seldom copious. The occurrence of syncope or of profound shock also helps to stop bleeding by reducing the force of the heart's action.

On the other hand, there are conditions which retard the natural arrest. When, for example, a vessel is only partly divided, the contraction and retraction of the muscular coat, instead of diminishing the calibre of the artery, causes the wound in the vessel to gape; by completing the division of the vessel under these circumstances the bleeding can often be arrested. In certain situations, also, the arteries are so intimately connected with their sheaths, that when cut across they were unable to retract and contract--for example, in the scalp, in the penis, and in bones--and copious bleeding may take place from comparatively small vessels. This inability of the vessels to contract and retract is met with also in inflamed and œdematous parts and in scar tissue. Arteries divided in the substance of a muscle also sometimes bleed unduly. Any increase in the force of the heart's action, such as may result from exertion, excitement, or over-stimulation, also interferes with the natural arrest. Lastly, in bleeders, there are conditions which interfere with the natural arrest of hæmorrhage.

#Repair of a Vessel ligated in its Continuity.#--When a ligature is applied to an artery it should be pulled sufficiently tight to occlude the lumen without causing rupture of its coats. It often happens, however, that the compression causes rupture of the inner and middle coats, so that only the outer coat remains in the grasp of the ligature. While this weakens the wall of the vessel, it has the advantage of hastening coagulation, by bringing the blood into contact with damaged tissue. Whether the inner and middle coats are ruptured or not, blood coagulates both above and below the ligature, the proximal clot being longer and broader than that on the distal side. In small arteries these clots extend as far as the nearest collateral branch, but in the larger trunks their length varies. The permanent occlusion of those portions of the vessel occupied by clot is brought about by the formation of granulation tissue, and its replacement by cicatricial tissue, so that the occluded segment of the vessel is represented by a fibrous cord. In this process the coagulum only plays a passive rôle by forming a scaffolding on which the granulation tissue is built up. The ligature surrounding the vessel, and the elements of the clot, are ultimately absorbed.

#Repair of Veins.#--The process of repair in veins is the same as that in arteries, but the thrombosed area may become canalised and the circulation through the vessel be re-established.

HÆMORRHAGE IN SURGICAL OPERATIONS

The management of the hæmorrhage which accompanies an operation includes (a) preventive measures, and (b) the arrest of the bleeding.

#Prevention of Hæmorrhage.#--Whenever possible, hæmorrhage should be controlled by _digital compression_ of the main artery supplying the limb rather than by a tourniquet. If efficiently applied compression reduces the immediate loss of blood to a minimum, and the bleeding from small vessels that follows the removal of the tourniquet is avoided. Further, the pressure of a tourniquet has been shown to be a material factor in producing shock.

In selecting a point at which to apply digital compression, it is essential that the vessel should be lying over a bone which will furnish the necessary resistance. The common carotid, for example, is pressed backward and medially against the transverse process (carotid tubercle) of the sixth cervical vertebra; the temporal against the temporal process (zygoma) in front of the ear; and the facial against the mandible at the anterior edge of the masseter.

In the upper extremity, the subclavian is pressed against the first rib by making pressure downwards and backwards in the hollow above the clavicle; the axillary and brachial by pressing against the shaft of the humerus.

In the lower extremity, the femoral is controlled by pressing in a direction backward and slightly upward against the brim of the pelvis, midway between the symphysis pubis and the anterior superior iliac spine.

The abdominal aorta may be compressed against the bodies of the lumbar vertebræ opposite the umbilicus, if the spine is arched well forwards over a pillow or sand-bag, or by the method suggested by Macewen, in which the patient's spine is arched forwards by allowing the lower extremities and pelvis to hang over the end of the table, while the assistant, standing on a stool, applies his closed fist over the abdominal aorta and compresses it against the vertebral column. Momburg recommends an elastic cord wound round the body between the iliac crest and the lower border of the ribs, but this procedure has caused serious damage to the intestine.

When digital compression is not available, the most convenient and certain means of preventing hæmorrhage--say in an amputation--is by the use of some form of _tourniquet_, such as the elastic tube of Esmarch or of Foulis, or an elastic bandage, or the screw tourniquet of Petit. Before applying any of these it is advisable to empty the limb of blood. This is best done after the manner suggested by Lister: the limb is held vertical for three or four minutes; the veins are thus emptied by gravitation, and they collapse, and as a physiological result of this the arteries reflexly contract, so that the quantity of blood entering the limb is reduced to a minimum. With the limb still elevated the tourniquet is firmly applied, a part being selected where the vessel can be pressed directly against a bone, and where there is no risk of exerting injurious pressure on the nerve-trunks. The tourniquet should be applied over several layers of gauze or lint to protect the skin, and the first turn of the tourniquet must be rapidly and tightly applied to arrest completely the arterial flow, otherwise the veins only are obstructed and the limb becomes congested. In the lower extremity the best place to apply a tourniquet is the middle third of the thigh; in the upper extremity, in the middle of the arm. A tourniquet should never be applied tighter or left on longer than is absolutely necessary.

The screw tourniquet of Petit is to be preferred when it is desired to intermit the flow through the main artery as in operations for aneurysm.

When a tourniquet cannot conveniently be applied, or when its presence interferes with the carrying out of the operation--as, for example, in amputations at the hip or shoulder--the hæmorrhage may be controlled by preliminary ligation of the main artery above the seat of operation--for instance, the external iliac or the subclavian. For such contingencies also the steel skewers used by Spence and Wyeth, or a special clamp or forceps, such as that suggested by Lynn Thomas, may be employed. In the case of vessels which it is undesirable to occlude permanently, such as the common carotid, the temporary application of a ligature or clamp is useful.

#Arrest of Hæmorrhage.#--_Ligature._--This is the best means of securing the larger vessels. The divided vessel having been caught with forceps as near to its cut end as possible, a ligature of catgut or silk is tied round it. When there is difficulty in applying a ligature securely, for example in a dense tissue like the scalp or periosteum, or in a friable tissue like the thyreoid gland or the mesentery, a stitch should be passed so as to surround the bleeding vessel a short distance from its end, in this way ensuring a better hold and preventing the ligature from slipping.

If the hæmorrhage is from a partly divided vessel, this should be completely cut across to enable its walls to contract and retract, and to facilitate the application of forceps and ligatures.

_Torsion._--This method is seldom employed except for comparatively small vessels, but it is applicable to even the largest arteries. In employing torsion, the end of the vessel is caught with forceps, and the terminal portion twisted round several times. The object is to tear the inner and middle coats so that they curl up inside the lumen, while the outer fibrous coat is twisted into a cord which occludes the end of the vessel.

_Forci-pressure._--Bleeding from the smallest arteries and from arterioles can usually be arrested by firmly squeezing them for a few minutes with artery forceps. It is usually found that on the removal of the forceps at the end of an operation no further hæmorrhage takes place. By the use of specially strong clamps, such as the angiotribes of Doyen, large trunks may be occluded by pressure.

_Cautery._--The actual cautery or Paquelin's thermo-cautery is seldom employed to arrest hæmorrhage, but is frequently useful in preventing it, as, for example, in the removal of piles, or in opening the bowel in colostomy. It is used at a dull-red heat, which sears the divided ends of the vessel and so occludes the lumen. A bright-red or a white heat cuts the vessel across without occluding it. The separation of the slough produced by the charring of the tissues is sometimes attended with secondary bleeding.

_Hæmostatics_ or _Styptics_.--The local application of hæmostatics is seldom to be recommended. In the treatment of epistaxis or bleeding from the nose, of hæmorrhage from the socket of a tooth, and sometimes from ulcerating or granulating surfaces, however, they may be useful. All clots must be removed and the drug applied directly to the bleeding surface. Adrenalin and turpentine are the most useful drugs for this purpose.

Hæmorrhage from bone, for example the skull, may be arrested by means of Horsley's aseptic plastic wax. To stop persistent oozing from soft tissues, Horsley successfully applied a portion of living vascular tissue, such as a fragment of muscle, which readily adheres to the oozing surface and yields elements that cause coagulation of the blood by thrombo-kinetic processes. When examined after two or three days the muscle has been found to be closely adherent and undergoing organisation.

#Arrest of Accidental Hæmorrhage.#--The most efficient means of temporarily controlling hæmorrhage is by pressure applied with the finger, or with a pad of gauze, directly over the bleeding point. While this is maintained an assistant makes digital pressure, or applies a tourniquet, over the main vessel of the limb on the proximal side of the bleeding point. A useful _emergency tourniquet_ may be improvised by folding a large handkerchief _en cravatte_, with a cork or piece of wood in the fold to act as a pad. The handkerchief is applied round the limb, with the pad over the main artery, and the ends knotted on the lateral aspect of the limb. With a strong piece of wood the handkerchief is wound up like a Spanish windlass, until sufficient pressure is exerted to arrest the bleeding.

When hæmorrhage is taking place from a number of small vessels, its arrest may be effected by elevation of the bleeding part, particularly if it is a limb. By this means the force of the circulation is diminished and the formation of coagula favoured. Similarly, in wounds of the hand or forearm, or of the foot or leg, bleeding may be arrested by placing a pad in the flexure and acutely flexing the limb at the elbow or knee respectively.

#Reactionary Hæmorrhage.#--Reactionary or intermediary hæmorrhage is really a recurrence of primary bleeding. As the name indicates, it occurs during the period of reaction--that is, within the first twelve hours after an operation or injury. It may be due to the increase in the blood-pressure that accompanies reaction displacing clots which have formed in the vessels, or causing vessels to bleed which did not bleed during the operation; to the slipping of a ligature; or to the giving way of a grossly damaged portion of the vessel wall. In the scrotum, the relaxation of the dartos during the first few hours after operation occasionally leads to reactionary hæmorrhage.

As a rule, reactionary hæmorrhage takes place from small vessels as a result of the displacement of occluding clots, and in many cases the hæmorrhage stops when the bandages and soaked dressings are removed. If not, it is usually sufficient to remove the clots and apply firm pressure, and in the case of a limb to elevate it. Should the hæmorrhage recur, the wound must be reopened, and ligatures applied to the bleeding vessels. Douching the wound with hot sterilised water (about 110° F.), and plugging it tightly with gauze, are often successful in arresting capillary oozing. When the bleeding is more copious, it is usually due to a ligature having slipped from a large vessel such as the external jugular vein after operations in the neck, and the wound must be opened up and the vessel again secured. The internal administration of heroin or morphin, by keeping the patient quiet, may prove useful in preventing the recurrence of hæmorrhage.

#Secondary Hæmorrhage.#--The term secondary hæmorrhage refers to bleeding that is delayed in its onset and is due to pyogenic infection of the tissues around an artery. The septic process causes softening and erosion of the wall of the artery so that it gives way under the pressure of the contained blood. The leakage may occur in drops, or as a rush of blood, according to the extent of the erosion, the size of the artery concerned, and the relations of the erosion to the surrounding tissues. When met with as a complication of a wound there is an interval--usually a week to ten days--between the receipt of the wound and the first hæmorrhage, this time being required for the extension of the septic process to the wall of the artery and the consequent erosion of its coats. When secondary hæmorrhage occurs apart from a wound, there is a similar septic process attacking the wall of the artery from the outside; for example in sloughing sore-throat, the separation of a slough may implicate the wall of an artery and be followed by serious and it may be fatal hæmorrhage. The mechanical pressure of a fragment of bone or of a rubber drainage tube upon the vessel may aid the septic process in causing erosion of the artery. In pre-Listerian days, the silk ligature around the artery likewise favoured the changes that lead to secondary hæmorrhage, and the interesting observation was often made, that when the collateral circulation was well established, the leakage occurred on the _distal_ side of the ligature. While it may happen that the initial hæmorrhage is rapidly fatal, as for example when the external carotid or one of its branches suddenly gives way, it is quite common to have one, two or more _warning hæmorrhages_ before the leakage on a large scale, which is rapidly fatal.

The _appearances of the wound_ in cases complicated by secondary hæmorrhage are only characteristic in so far that while obviously infected, there is an absence of all reaction; instead of frankly suppurating, there is little or no discharge and the surrounding cellular tissue and the limb beyond are œdematous and pit on pressure.

The _general symptoms_ of septic poisoning in cases of secondary hæmorrhage vary widely in severity: they may be so slight that the general health is scarcely affected and the convalescence from an operation, for example, may be apparently normal except that the wound does not heal satisfactorily. For example, a patient may be recovering from an operation such as the removal of an epithelioma of the mouth, pharynx or larynx and the associated lymph glands in the neck, and be able to be up and going about his room, when, suddenly, without warning and without obvious cause, a rush of blood occurs from the mouth or the incompletely healed wound in the neck, causing death within a few minutes.

On the other hand, the toxæmia may be of a profound type associated with marked pallor and progressive failure of strength, which, of itself, even when the danger from hæmorrhage has been overcome, may have a fatal termination. The _prognosis_ therefore in cases of secondary hæmorrhage can never be other than uncertain and unfavourable; the danger from loss of blood _per se_ is less when the artery concerned is amenable to control by surgical measures.

_Treatment._--The treatment of secondary hæmorrhage includes the use of local measures to arrest the bleeding, the employment of general measures to counteract the accompanying toxæmia, and when the loss of blood has been considerable, the treatment of the bloodless state.

_Local Measures to arrest the Hæmorrhage._--The occurrence of even slight hæmorrhages from a septic wound in the vicinity of a large blood vessel is to be taken seriously; it is usually necessary to _open up the wound_, clear out the clots and infected tissues with a sharp spoon, disinfect the walls of the cavity with eusol or hydrogen peroxide, and _pack_ it carefully but not too tightly with gauze impregnated with some antiseptic, such as "bipp," so that, if the bleeding does not recur, it may be left undisturbed for several days. The packing should if possible be brought into actual contact with the leaking point in the vessel, and so arranged as to make pressure on the artery above the erosion. The dressings and bandage are then applied, with the limb in the attitude that will diminish the force of the stream through the main artery, for example, flexion at the elbow in hæmorrhage from the deep palmar arch. Other measures for combating the local sepsis, such as the irrigation method of Carrel, may be considered.

If the wound involves one of the extremities, it may be useful; and it imparts confidence to the nurse, and, it may be, to the patient, if a Petit's tourniquet is loosely applied above the wound, which the nurse is instructed to tighten up in the event of bleeding taking place.

_Ligation of the Artery._--If the hæmorrhage recurs in spite of packing the wound, or if it is serious from the outset and likely to be critical if repeated, ligation of the artery itself or of the trunk from which it springs, at a selected spot higher up, should be considered. This is most often indicated in wounds of the extremities.

As examples of proximal ligation for secondary hæmorrhage may be cited ligation of the hypogastric artery for hæmorrhage in the buttock, of the common iliac for hæmorrhage in the thigh, of the brachial in the upper arm for hæmorrhage from the deep palmar arch, and of the posterior tibial behind the medial malleolus for hæmorrhage from the sole of the foot.

_Amputation_ is the last resource, and should be decided upon if the hæmorrhage recurs after proximal ligation, or if this has been followed by gangrene of the limb; it should also be considered if the nature of the wound and the virulence of the sepsis would of themselves justify removal of the limb. Every surgeon can recall cases in which a timely amputation has been the means of saving life.

The _counteraction of the toxæmia_ and the _treatment of the bloodless state_, are carried out on the usual lines.

#Hæmorrhage of Toxic Origin.#--Mention must also be made of hæmorrhages which depend upon infective or toxic conditions and in which no gross lesion of the vessels can be discovered. The bleeding occurs as an oozing, which may be comparatively slight and unimportant, or by its persistence may become serious. It takes place into the superficial layers of the skin, from mucous membranes, and into the substance of such organs as the pancreas. Hæmorrhage from the stomach and intestine, attended with a brown or black discoloration of the vomit and of the stools, is one of the best known examples: it is not uncommonly met with in infective conditions originating in the appendix, intestine, gall-bladder, and other abdominal organs. Hæmorrhage from the mucous membrane of the stomach after abdominal operations--apparently also due to toxic causes and not to the operation--gives rise to the so-called _post-operative hæmatemesis_.

#Constitutional Effects of Hæmorrhage.#--The severity of the symptoms resulting from hæmorrhage depends as much on the rapidity with which the bleeding takes place as on the amount of blood lost. The sudden loss of a large quantity, whether from an open wound or into a serous cavity--for example, after rupture of the liver or spleen--is attended with marked pallor of the surface of the body and coldness of the skin, especially of the face, feet, and hands. The skin is moist with a cold, clammy sweat, and beads of perspiration stand out on the forehead. The pulse becomes feeble, soft, and rapid, and the patient is dull and listless, and complains of extreme thirst. The temperature is usually sub-normal; and the respiration rapid, shallow, and sighing in character. Abnormal visual sensations, in the form of flashes of light or spots before the eyes; and rushing, buzzing, or ringing sounds in the ears, are often complained of.

In extreme cases, phenomena which have been aptly described as those of "air-hunger" ensue. On account of the small quantity of blood circulating through the body, and the diminished hæmoglobin content of the blood, the tissues are imperfectly oxygenated, and the patient becomes extremely restless, gasping for breath, constantly throwing about his arms and baring his chest in the vain attempt to breath more freely. Faintness and giddiness are marked features. The diminished supply of oxygen to the brain and to the muscles produces muscular twitchings, and sometimes convulsions. Finally the pupils dilate, the sphincters relax, and death ensues.

Young children stand the loss of blood badly, but they quickly recover, as the regeneration of blood takes place rapidly. In old people also, and especially when they are fat, the loss of blood is badly borne, and the ill effects last longer. Women, on the whole, stand loss of blood better than men, and in them the blood is more rapidly re-formed. A few hours after a severe hæmorrhage there is usually a leucocytosis of from 15,000 to 30,000.

#Treatment of the Bloodless State.#--The patient should be placed in a warm, well-ventilated room, and the foot of the bed elevated. Cardiac stimulants, such as strychnin or alcohol, must be judiciously administered, over-stimulation being avoided. The inhalation of oxygen has been found useful in relieving the urgent symptoms of dyspnœa.

The blood may be emptied from the limbs into the vessels of the trunk, where it is more needed, by holding them vertically in the air for a few minutes, and then applying a firm elastic bandage over a layer of cotton wool, from the periphery towards the trunk.

_Introduction of Fluids into the Circulation._--The most valuable measure for maintaining the circulation, however, is by transfusion of blood (_Op. Surg._, p. 37). If this is not immediately available the introduction of from one to three pints of physiological salt solution (a teaspoonful of common salt to a pint of water) into a vein, or a 6 per cent. solution of gum acacia, is a useful expedient. The solution is sterilised by boiling, and cooled to a temperature of about 105° F. The addition of 5 to 10 minims of adrenalin solution (1 in 1000) is advantageous in raising the blood-pressure (_Op. Surg._, p. 565).

When the intra-venous method is not available, one or two pints of saline solution with adrenalin should be slowly introduced into the rectum, by means of a long rubber tube and a filler. Satisfactory, although less rapidly obtained results follow the introduction of saline solution into the cellular tissue--for example, under the mamma, into the axilla, or under the skin of the back.

If the patient can retain fluids taken by the mouth--such as hot coffee, barley water, or soda water--these should be freely given, unless the injury necessitates operative treatment under a general anæsthetic.

Transfusion of blood is most valuable as _a preliminary to operation_ in patients who are bloodless as a result of hæmorrhage from gastric and duodenal ulcers, and in bleeders.

HÆMOPHILIA

The term hæmophilia is applied to an inherited disease which renders the patient liable to serious hæmorrhage from even the most trivial injuries; and the subjects of it are popularly known as "bleeders."

The cause of the disease and its true nature are as yet unknown. There is no proof of any structural defect in the blood vessels, and beyond the fact that there is a diminution in the number of blood-plates, it has not been demonstrated that there is any alteration in the composition of the blood.

The affection is in a marked degree hereditary, all the branches of an affected family being liable to suffer. Its mode of transmission to individuals, moreover, is characteristic: the male members of the stock alone suffer from the affection in its typical form, while the tendency is transmitted through the female line. Thus the daughters of a father who is a bleeder, whilst they do not themselves suffer from the disease, transmit the tendency to their male offspring. The sons, on the other hand, neither suffer themselves nor transmit the disease to their children (Fig. 64). The female members of a hæmophilic stock are often very prolific, and there is usually a predominance of daughters in their families.

FIG 64.--Genealogical Tree of a Hæmophilic Family.

Great-Great-Grandmother                Great-Great-Grandfather Mrs D. (Lancashire) F                  M (History not known                   .|                  |  as to bleeding)                   .|                  |                   .+----------+-------+                   ............| .|                           ....|                           .+---------+--------+       Great-Grandmother .|         |        |       (Married three .F        MB       MB         times)   .|                     .|                           .|      By First Husband     .|                  By Second           By Third              ..............|                  Husband             Husband   +-----------+------------+----------+-------+-------+-----------+------+   |          .|            |          |       +-------+-----------+------+   M          .F            F          F       |       |           +------+   |          .|            |          |       MB      F Died in      No Died       Grandmother      |          |               | Childbed    Family æt.          .|            |     +-----------+   +----+--- 70          .|        +------+  |had family |   |              .|        |      |  |but history|   |              .|        MB    MB  |not known  | MB              .|              .|              .|............................. +-----+----------+------------+------------+------------+-------------+ |    |          |            |            |.           |             | |   |          |            |            |.           |             | M   M          M            MB           F.           F             F    |                                    |.           |             |    |                                  Mother   +--+--+---+--+--+   |   +----+                                 |.     |  |  |   |  |  |   |   |    |                                 |.     M  M  MB  F  F  F   |   M    F                                 |.                         |     Not Married                           |.             +---+---+---+---+                                           |.             |   |   |   |   |                                           |.             MB  M   MB  M   M                              .............|.                         +-----+-----+-----+-----+-----+                         |    .|    .|     |     |     |                         |    .|*   .|*    |     |     |                         M    MB    MB     F     F     F

F = Females. M = Males (not bleeders). MB = Males (bleeders)

** the patients observed by the authors. The dotted line shows the transmission of the disease to our patients through four generations.

The disease is met with in boys who are otherwise healthy, and usually manifests itself during the first few years of life. In rare instances profuse hæmorrhage takes place when the umbilical cord separates. As a rule the first evidence is the occurrence of long-continued and uncontrollable bleeding from a comparatively slight injury, such as the scratch of a pin, the extraction of a tooth, or after the operation of circumcision. The blood oozes slowly from the capillaries; at first it appears normal, but after flowing for some days, or it may be weeks, it becomes pale, thin, and watery, and shows less and less tendency to coagulate.

Female members of hæmophilia families sometimes show a tendency to excessive hæmorrhage, but they seldom manifest the characteristic features met with in the male members.

Sometimes the hæmorrhage takes place apparently spontaneously from the gums, the nasal or the intestinal mucous membrane. In other cases the bleeding occurs into the cellular tissue under the skin or mucous membrane, producing large areas of ecchymosis and discoloration. One of the commonest manifestations of the disease is the occurrence of hæmorrhage into the cavities of the large joints, especially the knee, elbow, or hip. The patient suffers repeatedly from such hæmorrhages, the determining injury being often so slight as to have passed unobserved.

There is evidence that the tendency to bleed is greater at certain times than at others--in some cases showing almost a cyclical character--although nothing is known as to the cause of the variation.

After a severe hæmorrhage into the cellular tissue or into a joint, the patient becomes pale and anæmic, the temperature may rise to 102° or 103° F., the pulse become small and rapid, and hæmic murmurs are sometimes developed over the heart and large arteries. The swelling is tense, fluctuating, and hot, and there is considerable pain and tenderness.

In exceptional cases, blisters form over the seat of the effusion, or the skin may even slough, and the clinical features may therefore come to simulate closely those of an acute suppurative condition. When the skin sloughs, an ulcer is formed with altered blood-clot in its floor like that seen in scurvy, and there is a remarkable absence of any attempt at healing.

The acute symptoms gradually subside, and the blood is slowly absorbed, the discoloration of the skin passing through the same series of changes as occur after an ordinary bruise. The patients seldom manifest the symptoms of the bloodless state, and the blood is rapidly regenerated.

The _diagnosis_ is easy if the patient or his friends are aware of the family tendency to hæmorrhage and inform the doctor of it, but they are often sensitive and reticent regarding the fact, and it may only be elicited after close investigation. From the history it is usually easy to exclude scurvy and purpura. Repeated hæmorrhages into a joint may result in appearances which closely simulate those of tuberculous disease. Recent hæmorrhages into the cellular tissue often present clinical features closely resembling those of acute cellulitis or osteomyelitis. A careful examination, however, may reveal ecchymoses on other parts of the body which give a clue to the nature of the condition, and may prevent the disastrous consequences that may follow incision.

These patients usually succumb sooner or later to hæmorrhage, although they often survive several severe attacks. After middle life the tendency to bleed appears to diminish.

_Treatment._--As a rule the ordinary means of arresting hæmorrhage are of little avail. From among the numerous means suggested, the following may be mentioned: The application to the bleeding point of gauze soaked in a 1 in 1000 solution of adrenalin; prolonged inhalation of oxygen; freezing the part with a spray of ethyl-chloride; one or more subcutaneous injections of gelatin--5 ounces of a 2½ per cent. solution of white gelatin in normal salt solution being injected at a temperature of about 100° F.; the injection of pituitary extract. The application of a pad of gauze soaked in the blood of a normal person sometimes arrests the bleeding.

To prevent bleeding in hæmophilics, intra-venous or subcutaneous injections of fresh blood serum, taken from the human subject, the sheep, the dog, or the horse, have proved useful. If fresh serum is not available, anti-diphtheritic or anti-tetanic serum or trade preparations, such as hemoplastin, may be employed. We have removed the appendix and amputated through the thigh in hæmophilic subjects without excessive loss of blood after a course of fresh sheep's serum given by the mouth over a period of several weeks.

The chloride and lactate of calcium, and extract of thymus gland have been employed to increase the coagulability of the blood. The patient should drink large quantities of milk, which also increases the coagulability of the blood. Monro has observed remarkable results from the hypodermic injection of emetin hydrochloride in ½-grain doses.

THROMBOSIS AND EMBOLISM

The processes known as thrombosis and embolism are so intimately associated with the diseases of blood vessels that it is convenient to define these terms in the first instance.

#Thrombosis.#--The term _thrombus_ is applied to a clot of blood formed in the interior of the heart or of a blood vessel, and the process by which such a clot forms is known as _thrombosis_. It would appear that slowing or stagnation of the blood-stream, and interference with the integrity of the lining membrane of the vessel wall, are the most important factors determining the formation of the clot. Alterations in the blood itself, such as occur, for example, in certain toxæmias, also favour coagulation. When the thrombus is formed slowly, it consists of white blood cells with a small proportion of fibrin, and, being deposited in successive layers, has a distinctly laminated appearance on section. It is known as a _white thrombus_ or laminated clot, and is often met with in the sac of an aneurysm (Fig. 72). When rapidly formed in a vessel in which the blood is almost stagnant--as, for example, in a pouched varicose vein--the blood coagulates _en masse_, and the clot consists of all the elements of the blood, constituting a _red thrombus_ (Fig. 66). Sometimes the thrombus is _mixed_--a red thrombus being deposited on a white one, it may be in alternate layers.

When aseptic, a thrombus may become detached and be carried off in the blood-stream as an embolus; it may become organised; or it may degenerate and undergo calcification. Occasionally a small thrombus situated behind a valve in a varicose vein or in the terminal end of a dilated vein--for example in a pile--undergoes calcification, and is then spoken of as a _phlebolith_; it gives a shadow with the X-rays.

When infected with pyogenic bacteria, the thrombus becomes converted into pus and a localised abscess forms; or portions of the thrombus may be carried as emboli in the circulation to distant parts, where they give rise to secondary foci of suppuration--pyæmic abscesses.

#Embolism.#--The term _embolus_ is applied to any body carried along in the circulation and ultimately becoming impacted in a blood vessel. This occurrence is known as _embolism_. The commonest forms of embolus are portions of thrombi or of fibrinous formations on the valves of the heart, the latter being usually infected with micro-organisms.

Embolism plays an important part in determining one form of gangrene, as has already been described. Infective emboli are the direct cause of the secondary abscesses that occur in pyæmia; and they are sometimes responsible for the formation of aneurysm.

Portions of malignant tumours also may form emboli, and their impaction in the vessels may lead to the development of secondary growths in distant parts of the body.

Fat and air embolism have already been referred to.

ARTERITIS

_Pyogenic._--Non-suppurative inflammation of the coats of an artery may so soften the wall of the vessel as to lead to aneurysmal dilatation. It is not uncommon in children, and explains the occurrence of aneurysm in young subjects.

When suppuration occurs, the vessel wall becomes disintegrated and gives way, leading to secondary hæmorrhage. If the vessel ruptures into an abscess cavity, dangerous bleeding may occur when the abscess bursts or is opened.

_Syphilitic._--The inflammation associated with syphilis results in thickening of the tunica intima, whereby the lumen of the vessel becomes narrowed, or even obliterated--_endarteritis obliterans_. The middle coat usually escapes, but the tunica externa is generally thickened. These changes cause serious interference with the nutrition of the parts supplied by the affected arteries. In large trunks, by diminishing the elasticity of the vessel wall, they are liable to lead to the formation of aneurysm.

Changes in the arterial walls closely resembling those of syphilitic arteritis are sometimes met with in _tuberculous_ lesions.

#Arterio-sclerosis# or #Chronic Arteritis#.--These terms are applied to certain changes which result in narrowing of the lumen and loss of elasticity in the arteries. The condition may affect the whole vascular system or may be confined to particular areas. In the smaller arteries there is more or less uniform thickening of the tunica intima from proliferation of the endothelium and increase in the connective tissue in the elastic lamina--a form of obliterative endarteritis. The narrowing of the vessels may be sufficient to determine gangrene in the extremities. In course of time, particularly in the larger arteries, this new tissue undergoes degeneration, at first of a fatty nature, but progressing in the direction of calcification, and this is followed by the deposit of lime salts in the young connective tissue and the formation of calcareous plates or rings over a considerable area of the vessel wall. To this stage in the process the term _atheroma_ is applied. The endothelium over these plates often disappears, leaving them exposed to the blood-stream.

Changes of a similar kind sometimes occur in the middle coat, the lime salts being deposited among the muscle fibres in concentric rings.

The primary cause of arterio-sclerosis is not definitely known, but its almost constant occurrence, to a greater or less degree, in the aged suggests that it is of the nature of a senile degeneration. It is favoured by anything which throws excessive strain on the vessel walls, such as heavy muscular work; by chronic alcoholism and syphilis; or by such general diseases as tend to raise the blood-pressure--for example, chronic Bright's disease or gout. It occurs with greater frequency and with greater severity in men than in women.

Atheromatous degeneration is most common in the large arterial trunks, and the changes are most marked at the arch of the aorta, opposite the flexures of joints, at the mouths of large branches, and at parts where the vessel lies in contact with bone. The presence of diseased patches in the wall of an artery diminishes its elasticity and favours aneurysmal dilatation. Such a vessel also is liable to be ruptured by external violence and so give rise to traumatic aneurysm. Thrombosis is liable to occur when calcareous plates are exposed in the lumen of the vessel by destruction of the endothelium, and this predisposes to embolism. Arterio-sclerosis also interferes with the natural arrest of hæmorrhage, and by rendering the vessels brittle, makes it difficult to secure them by ligature. In advanced cases the accessible arteries--such as the radial, the temporal or the femoral--may be felt as firm, tortuous cords, which are sometimes so hard that they have been aptly compared to "pipe-stems." The pulse is smaller and less compressible than normal, and the vessel moves bodily with each pulsation. It must be borne in mind, however, that the condition of the radial artery may fail to afford a clue to that of the larger arteries. Calcified arteries are readily identified in skiagrams (Fig. 65).

[Illustration: FIG. 65.--Radiogram showing Calcareous Degeneration (Atheroma) of Arteries.]

We have met with a chronic form of arterial degeneration in elderly women, affecting especially the great vessels at the root of the neck, in which the artery is remarkably attenuated and dilated, and so friable that the wall readily tears when seized with an artery-forceps, rendering ligation of the vessel in the ordinary way well-nigh impossible. Matas suggests infolding the wall of the vessel with interrupted sutures that do not pierce the intima, and wrapping it round with a strip of peritoneum or omentum.

The most serious form of arterial _thrombosis_ is that met with _in the abdominal aorta_, which is attended with violent pains in the lower limbs, rapidly followed by paralysis and arrest of the circulation.

THROMBO-PHLEBITIS AND THROMBOSIS IN VEINS

#Thrombosis# is more common in veins than in arteries, because slowing of the blood-stream and irritation of the endothelium of the vessel wall are, owing to the conditions of the venous circulation, more readily induced in veins.

Venous thrombosis may occur from purely mechanical causes--as, for example, when the wall of a vein is incised, or the vessel included in a ligature, or when it is bruised or crushed by a fragment of a broken bone or by a bandage too tightly applied. Under these conditions thrombosis is essentially a reparative process, and has already been considered in relation to the repair of blood vessels.

In other cases thrombosis is associated with certain constitutional diseases--gout, for example; the endothelium of the veins undergoing changes--possibly the result of irritation by abnormal constituents in the blood--which favour the formation of thrombi.

Under these various conditions the formation of a thrombus is not necessarily associated with the action of bacteria, although in any of them this additional factor may be present.

The most common cause of venous thrombosis, however, is inflammation of the wall of the vein--phlebitis.

#Phlebitis.#--Various forms of phlebitis are met with, but for practical purposes they may be divided into two groups--one in which there is a tendency to the formation of a thrombus; the other in which the infective element predominates.

In surgical patients, the _thrombotic form_ is almost invariably met with in the lower extremity, and usually occurs in those who are debilitated and anæmic, and who are confined to bed for prolonged periods--for example, during the treatment of fractures of the leg or pelvis, or after such operations as herniotomy, prostatectomy, or appendectomy.

_Clinical Features._--The most typical example of this form of phlebitis is that so frequently met with in the great saphena vein, especially when it is varicose. The onset of the attack is indicated by a sudden pain in the lower limb--sometimes below, sometimes above the knee. This initial pain may be associated with shivering or even with a rigor, and the temperature usually rises one or two degrees. There is swelling and tenderness along the line of the affected vein, and the skin over it is a dull-red or purple colour. The swollen vein may be felt as a firm cord, with bead-like enlargements in the position of the valves. The patient experiences a feeling of stiffness and tightness throughout the limb. There is often œdema of the leg and foot, especially when the limb is in the dependent position. The acute symptoms pass off in a few days, but the swelling and tenderness of the vein and the œdema of the limb may last for many weeks.

When the deep veins--iliac, femoral, popliteal--are involved, there is great swelling of the whole limb, which is of a firm almost "wooden" consistence, and of a pale-white colour; the œdema may be so great that it is impossible to feel the affected vein until the swelling has subsided. This is most often seen in puerperal women, and is known as _phlegmasia alba dolens_.

_Treatment._--The patient must be placed at absolute rest, with the foot of the bed raised on blocks 10 or 12 inches high, and the limb immobilised by sand-bags or splints. It is necessary to avoid handling the parts, lest the clot be displaced and embolism occur. To avoid frequent movement of the limb, the necessary dressings should be kept in position by means of a many-tailed rather than a roller bandage.

To relieve the pain, warm fomentations or lead and opium lotion should be applied. Later, ichthyol-glycerin, or glycerin and belladonna, may be substituted.

When, at the end of three weeks, the danger of embolism is past, douching and gentle massage may be employed to disperse the œdema; and when the patient gets up he should wear a supporting elastic bandage.

The _infective_ form usually begins as a peri-phlebitis arising in connection with some focus of infection in the adjacent tissues. The elements of the vessel wall are destroyed by suppuration, and the thrombus in its lumen becomes infected with pyogenic bacteria and undergoes softening.

_Occlusion of the inferior vena cava_ as a result of infective thrombosis is a well-known condition, the thrombosis extending into the main trunk from some of its tributaries, either from the femoral or iliac veins below or from the hepatic veins above.

Portions of the softened thrombus are liable to become detached and to enter the circulating blood, in which they are carried as emboli. These may lodge in distant parts, and give rise to secondary foci of suppuration--pyæmic abscesses.

_Clinical Features._--Infective phlebitis is most frequently met with in the transverse sinus as a sequel to chronic suppuration in the mastoid antrum and middle ear. It also occurs in relation to the peripheral veins, but in these it can seldom be recognised as a separate entity, being merged in the general infective process from which it takes origin. Its occurrence may be inferred, if in the course of a suppurative lesion there is a sudden rise of temperature, with pain, redness, and swelling along the line of a venous trunk, and a rapidly developed œdema of the limb, with pitting of the skin on pressure. In rare cases a localised abscess forms in the vein and points towards the surface.

_Treatment._--Attention must be directed towards the condition with which the phlebitis is associated. Ligation of the vein on the cardiac side of the thrombus with a view to preventing embolism is seldom feasible in the peripheral veins, although, as will be pointed out later, the jugular vein is ligated with this object in cases of phlebitis of the transverse sinus.

VARIX--VARICOSE VEINS

The term varix is applied to a condition in which veins are so altered in structure that they remain permanently dilated, and are at the same time lengthened and tortuous. Two types are met with: one in which dilatation of a large superficial vein and its tributaries is the most obvious feature; the other, in which bunches of distended and tortuous vessels develop at one or more points in the course of a vein, a condition to which Virchow applied the term _angioma racemosum venosum_. The two types may occur in combination.

Any vein in the body may become varicose, but the condition is rare except in the veins of the lower extremity, in the veins of the spermatic cord (varicocele), and in the veins of the anal canal (hæmorrhoids).

We are here concerned with varix as it occurs in the veins of the lower extremity.

_Etiology._--Considerable difference of opinion exists as to the essential cause of varix. The weight of evidence is in favour of the view that, when dilatation is the predominant element, it results from a congenital deficiency in the number, size, and strength of the valves of the affected veins, and in an inherent weakness in the vessel walls. The _angioma racemosum venosum_ is probably also due to a congenital alteration in the structure of the vessels, and is allied to tumours of blood vessels. The view that varix is congenital in origin, as was first suggested by Virchow, is supported by the fact that in a large proportion of cases the condition is hereditary; not only may several members of the same family in succeeding generations suffer from varix, but it is often found that the same vein, or segment of a vein, is involved in all of them. The frequent occurrence of varix in youth is also an indication of its congenital origin.

In the majority of cases it is only when some exciting factor comes into operation that the clinical phenomena associated with varix appear. The most common exciting cause is increased pressure within the veins, and this may be produced in a variety of ways. In certain diseases of the heart, lungs, and liver, for example, the venous pressure may be so raised as to cause a localised dilatation of such veins as are congenitally weak. The direct pressure of a tumour, or of the gravid uterus on the large venous trunks in the pelvis, may so obstruct the flow as to distend the veins of the lower extremity. It is a common experience in women that the signs of varix date from an antecedent pregnancy. The importance of the wearing of tight garters as a factor in the production of varicose veins has been exaggerated, although it must be admitted that this practice is calculated to aggravate the condition when it is once established. It has been proved experimentally that the backward pressure in the veins may be greatly increased by straining, a fact which helps to explain the frequency with which varicosity occurs in the lower limbs of athletes and of those whose occupation involves repeated and violent muscular efforts. There is reason to believe, moreover, that a sudden strain may, by rupturing the valves and so rendering them incompetent, induce varicosity independently of any congenital defect. Prolonged standing or walking, by allowing gravity to act on the column of blood in the veins of the lower limbs, is also an important determining factor in the production of varix.

Thrombosis of the deep veins--in the leg, for example--may induce marked dilatation of the superficial veins, by throwing an increased amount of work upon them. This is to be looked upon rather as a compensatory hypertrophy of the superficial vessels than as a true varix.

_Morbid Anatomy._--In the lower extremity the varicosity most commonly affects the vessels of the great saphena system; less frequently those of the small saphena system. Sometimes both systems are involved, and large communicating branches may develop between the two.

The essential lesion is the absence or deficiency of valves, so that they are incompetent and fail to support the column of blood which bears back upon them. Normally the valves in the femoral and iliac veins and in the inferior vena cava are imperfectly developed, so that in the erect posture the great saphena receives a large share of the backward pressure of the column of venous blood.

The whole length of the vein may be affected, but as a rule the disease is confined to one or more segments, which are not only dilated, but are also increased in length, so that they become convoluted. The adjacent loops of the convoluted vein are often bound together by fibrous tissue. All the coats are thickened, chiefly by an increased development of connective tissue, and in some cases changes similar to those of arterio-sclerosis occur. The walls of varicose veins are often exceedingly brittle. In some cases the thickening is uniform, and in others it is irregular, so that here and there thin-walled sacs or pouches project from the side of the vein. These pouches vary in size from a bean to a hen's egg, the larger forms being called _venous cysts_, and being most commonly met with in the region of the saphenous opening and of the opening in the popliteal fascia. Such pouches, being exposed to injury, are frequently the seat of thrombosis (Fig. 66).

[Illustration: FIG. 66.--Thrombosis in Tortuous and Pouched Great Saphena Vein, in longitudinal section.]

_Clinical Features._--Varix is most frequently met with between puberty and the age of thirty, and the sexes appear to suffer about equally.

The amount of discomfort bears no direct proportion to the extent of the varicosity. It depends rather upon the degree of pressure in the veins, as is shown by the fact that it is relieved by elevation of the limb. When the whole length of the main trunk of the great saphena is implicated, the pressure in the vein is high and the patient suffers a good deal of pain and discomfort. When, on the contrary, the upper part of the saphena and its valves are intact, and only the more distal veins are involved, the pressure is not so high and there is comparatively little suffering. The usual complaint is of a sense of weight and fulness in the limb after standing or walking, sometimes accompanied by actual pain, from which relief is at once obtained by raising the limb. Cramp-like pains in the muscles are often associated with varix of the deep veins.

The dilated and tortuous vein can be readily seen and felt when the patient is examined in the upright posture. In advanced cases, bead-like swellings are sometimes to be detected over the position of the valves, and, on running the fingers along the course of the vessel, a firm ridge, due to periphlebitis, may be detected on each side of the vein. When the limb is œdematous, the outline of the veins is obscured, but they can be identified on palpation as gutter-like tracks. When large veins are implicated, a distinct impulse on coughing may be seen to pass down as far as the knee; and if the vessel is sharply percussed a fluid wave may be detected passing both up and down the vein.

If the patient is placed on a couch and the limb elevated, the veins are emptied, and if pressure is then made over the region of the saphenous opening and the patient allowed to stand up, so long as the great saphena system alone is involved, the veins fill again very slowly from below. If the small saphena system also is involved, and if communicating branches are dilated, the veins fill up from below more rapidly. When the pressure over the saphenous opening is removed, the blood rapidly rushes into the varicose vessels from above; this is known as Trendelenburg's test.

The most marked dilatation usually occurs on the medial side of the limb, between the middle of the thigh and the middle of the calf, the arrangement of the veins showing great variety (Fig. 67).

There are usually one or more bunches of enlarged and tortuous veins in the region of the knee. Frequently a large branch establishes a communication between the systems of the great and small saphenous veins in the region of the popliteal space, or across the front of the upper part of the tibia. The superficial position of this last branch and its proximity to the bone render it liable to injury.

[Illustration: FIG. 67.--Extensive Varix of Internal Saphena System on Left Leg, of many years' standing.]

The small veins of the skin of the ankle and foot often show as fine blue streaks arranged in a stellate or arborescent manner, especially in women who have borne children.

_Complications._--When the varix is of long standing, the skin in the lower part of the leg sometimes assumes a mahogany-brown or bluish hue, as a result of the _deposit of blood pigment_ in the tissues, and this is frequently a precursor of ulceration.

_Chronic dermatitis_ (_varicose eczema_) is often met with in the lower part of the leg, and is due to interference with the nutrition of the skin. The incompetence of the valves allows the pressure in the varicose veins to equal that in the arterioles, so that the capillary circulation is impeded. From the same cause the blood in the deep veins is enabled to enter the superficial veins, where the backward pressure is so great that the blood flows down again, and so a vicious circle is established. The blood therefore loses more and more of its oxygen, and so fails to nourish the tissues.

The _ulcer_ of the leg associated with varicose veins has already been described.

_Hæmorrhage_ may take place from a varicose vein as a result of a wound or of ulceration of its wall. Increased intra-venous pressure produced by severe muscular strain may determine rupture of a vein exposed in the floor of an ulcer. If the limb is dependent, the incompetency of the valves permits of rapid and copious bleeding, which may prove fatal, particularly if the patient is intoxicated when the rupture takes place and no means are taken to arrest the hæmorrhage. The bleeding may be arrested at once by elevating the limb, or by applying pressure directly over the bleeding point.

_Phlebitis and thrombosis_ are common sequelæ of varix, and may prove dangerous, either by spreading into the large venous trunks or by giving rise to emboli. The larger the varix the greater is the tendency for a thrombus to spread upwards and to involve the deep veins. Thrombi usually originate in venous cysts or pouches, and at acute bends on the vessel, especially when these are situated in the vicinity of the knee, and are subjected to repeated injuries--for example in riding. Phleboliths sometimes form in such pouches, and may be recognised in a radiogram. In a certain proportion of cases, especially in elderly people, the occurrence of thrombosis leads to cure of the condition by the thrombus becoming organised and obliterating the vein.

_Treatment._--At best the treatment of varicose veins is only palliative, as it is obviously impossible to restore to the vessels their normal structure. The patient must avoid wearing anything, such as a garter, which constricts the limb, and any obvious cause of direct pressure on the pelvic veins, such as a tumour, persistent constipation, or an ill-fitting truss, should be removed. Cardiac, renal, or pulmonary causes of venous congestion must also be treated, and the functions of the liver regulated. Severe forms of muscular exertion and prolonged standing or walking are to be avoided, and the patient may with benefit rest the limb in an elevated position for a few hours each day. To support the distended vessels, a closely woven silk or worsted stocking, or a light and porous form of elastic bandage, applied as a puttee, should be worn. These appliances should be put on before the patient leaves his bed in the morning, and should only be removed after he lies down at night. In this way the vessels are never allowed to become dilated. Elastic stockings, and bandages made entirely of india-rubber, are to be avoided. In early and mild cases these measures are usually sufficient to relieve the patient's discomfort.

_Operative Treatment._--In aggravated cases, when the patient is suffering pain, when his occupation is interfered with by repeated attacks of phlebitis, or when there are large pouches on the veins, operative treatment is called for. The younger the patient the clearer is the indication to operate. It may be necessary to operate to enable a patient to enter one of the public services, even although no symptoms are present. The presence of an ulcer does not contra-indicate operation; the ulcer should be excised, and the raw surface covered with skin grafts, before dealing with the veins.

The _operation of Trendelenburg_ is especially appropriate to cases in which the trunk of the great saphena vein in the thigh is alone involved. It consists in exposing three or four inches of the vein in its upper part, applying a ligature at the upper and lower ends of the exposed portion, and, after tying all tributary branches, resecting this portion of the vein.

The procedure of C. H. Mayo is adapted to cases in which it is desirable to remove longer segments of the veins. It consists in the employment of special instruments known as "ring-enucleators" or "vein-strippers," by means of which long portions of the vein are removed through comparatively small incisions.

An alternative procedure consists in avulsing segments of the vein by means of Babcock's stylet, which consists of a flexible steel rod, 30 inches in length, with acorn-shaped terminals. The instrument is passed along the lumen of the segment to be dealt with, and a ligature applied around the vein above the bulbous end of the stylet enables nearly the whole length of the great saphena vein to be dragged out in one piece. These methods are not suitable when the veins are brittle, when there are pouches or calcareous deposits in their walls, or where there has been periphlebitis binding the coils together.

Mitchell of Belfast advises exposing the varices at numerous points by half-inch incisions, and, after clamping the vein between two pairs of forceps, cutting it across and twisting out the segments of the vein between adjacent incisions. The edges of the incisions are sutured; and the limb is firmly bandaged from below upwards, and kept in an elevated position. We have employed this method with satisfactory results.

The treatment of the complications of varix has already been considered.

ANGIOMA[4]

[4] In the description of angiomas we have followed the teaching of the late John Duncan.

Tumours of blood vessels may be divided, according to the nature of the vessels of which they are composed, into the capillary, the venous, and the arterial angiomas.

CAPILLARY ANGIOMA

The most common form of capillary angioma is the nævus or congenital telangiectasis.

#Nævus.#--A nævus is a collection of dilated capillaries, the afferent arterioles and the efferent venules of which often share in the dilatation. Little is known regarding the _etiology_ of nævi beyond the fact that they are of congenital origin. They often escape notice until the child is some days old, but attention is usually drawn to them within a fortnight of birth. For practical purposes the most useful classification of nævi is into the cutaneous, the subcutaneous, and the mixed forms.

_The cutaneous nævus_, "mother's mark," or "port-wine stain," consists of an aggregation of dilated capillaries in the substance of the skin. On stretching the skin the vessels can be seen to form a fine network, or to run in leashes parallel to one another. A dilated arteriole or a vein winding about among the capillaries may sometimes be detected. These nævi occur on any part of the body, but they are most frequently met with on the face. They may be multiple, and vary greatly in size, some being no bigger than a pin-head, while others cover large areas of the body. In colour they present every tint from purple to brilliant red; in the majority there is a considerable dash of blue, especially in cold weather.

Unlike the other forms of nævi, the cutaneous variety shows little tendency to disappear, and it is especially persistent when associated with overgrowth of the epidermis and of the hairs--_nævoid mole_.

The _treatment_ of the cutaneous nævus is unsatisfactory, owing to the difficulty of removing the nævus without leaving a scar which is even more disfiguring. Very small nævi may be destroyed by a fine pointed Paquelin thermo-cautery, or by escharotics, such as nitric acid. For larger nævi, radium and solidified carbon dioxide ("CO₂ snow") may be used. The extensive port-wine stains so often met with on the face are best left alone.

The _subcutaneous nævus_ is comparatively rare. It constitutes a well-defined, localised tumour, which may possess a distinct capsule, especially when it has ceased to grow or is retrogressing. On section, it presents the appearance of a finely reticulated sponge.

Although it may be noticed at, or within a few days of, birth, a subcutaneous nævus is often overlooked, especially when on a covered part of the body, and may not be discovered till the patient is some years old. It forms a rounded, lobulated swelling, seldom of large size and yielding a sensation like that of a sponge; the skin over it is normal, or may exhibit a bluish tinge, especially in cold weather. In some cases the tumour is diminished by pressing the blood out of it, but slowly fills again when the pressure is relaxed, and it swells up when the child struggles or cries. From a cold abscess it is diagnosed by the history and progress of the swelling and by the absence

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