ARTERY, PATHOLOGICAL CONDITIONS OF. 



and subsequently in the largest portion of its 

 circumference, of the cellular coat alone. The 

 long continuance and gradual increase of some 

 aneurisms, as contrasted with their sudden and 

 rapid growth afterwards, have been explained 

 on this supposition. 



Diffused aneurism. An aneurism is termed 

 diffused when the blood, removed from the 

 circulation, is not confined within a pouch or 

 sac, and therefore passes in every direction 

 throughout the cellular tissue of the limb. 

 This may be occasioned by the rupture or 

 ulceration of an aneurismal sac, but far more 

 frequently by some violence applied to the artery 

 itself in such a manner as to open its cellular 

 as well as its other coats. Thus a spicula of a 

 fractured bone, or a pointed sequestrum, in 

 coming from a necrosed limb, may produce the 

 disease ; but the most common examples that 

 fall under a surgeon's observation are furnished 

 by awkward or ignorant persons in their at- 

 tempts to perform the operation of phlebotomy. 

 In the latter case there is an external wound 

 communicating with the injured vessel, and 

 then it also presents a familiar illustration of 

 traumatic aneurism. 



When the blood is thus diffused throughout 

 the cellular tissue, there is always the greatest 

 danger ; not so much from the loss of a large 

 quantity to the circulation as from the rapidity 

 with which a limb so circumstanced runs into 

 a gangrene, a rapidity so great that the mor- 

 tification either is not or seems not to be pre- 

 ceded by inflammation, and its occurrence is 

 often the first notice a surgeon receives of the 

 extent and nature of the accident. When the 

 injured artery lies deep and is covered by a 

 dense and resisting fascia (as in the instance 

 of the posterior tibial artery being ruptured by 

 a blow), it may bleed for some time without 

 affording any indication beyond the pain and 

 tension complained of by the patient, and a 

 slight tumefaction of the limb. When, how- 

 ever, the fascia has yielded or sloughed and per- 

 mitted a more extended diffusion of the blood, 

 the part becomes swollen, glassy, and cedema- 

 tous, pale if the blood did not occupy the 

 cellular tissue underneath, but of a livid colour, 

 like that of a bruise, if it does. The joints 

 in the neighbourhood are kept flexed, and any 

 attempt at motion gives intolerable pain. In a 

 very short space of time circumscribed spots 

 of gangrene appear, which, on separating, per- 

 mit masses of very dark coagula to protrude, 

 accompanied by an oozing, or perhaps, a flow 

 of arterial blood, under which a patient will 

 very soon sink. And it may be, the real nature 

 of the case has not been suspected until this 

 blood has made its appearance. Doubtless, if 

 a diffused aneurism has been occasioned by a 

 wound, the rush of blood at the moment, its 

 colour, and the difficulty of controlling the hae- 

 morrhage will point out what has happened ; 

 or if there had been a circumscribed aneurism 

 that on a sudden lost its defined character 

 while the limb began to enlarge above and below 

 it, there would be good grounds for suspicion ; 

 but in any other case it is so difficult to sepa- 

 rate the pain and tension and the other symp- 



237 



toms from those which might naturally super- 

 vene on a severe injury, that the appearance of 

 a tendency to gangrene is too often the first 

 circumstance to create alarm. There are many 

 symptoms in which the diffused aneurism 

 differs from the circumscribed, that render 

 the diagnosis of the former particularly diffi- 

 cult. It has been already stated that the 

 " bruit de soufflet" is, even when present, not a 

 pathognomonic symptom, and if the vessel lies 

 deep it is not to be heard at all. Pulsation of 

 the tumour, the most satisfactory symptom of 

 an aneurism, is generally absent, and when 

 otherwise, is very weak, fluctuating, and indis- 

 tinct. To those who reflect that the effused 

 blood is thrown out amongst inelastic and 

 unresisting structures, that no portion of it is 

 returned to the circulation, but that it lies 

 a coagulated mass amongst the surrounding 

 cellular tissue, the absence of these symptoms 

 will not require explanation. 



Traumatic aneurism. But if, as very fre- 

 quently happens, the accident that caused the 

 aneurism has also created an external wound 

 communicating with the injured vessel, and 

 permitting the escape of a portion of the blood 

 through it, although still a diffused aneurism, 

 the leading circumstances of the case are 

 essentially altered. This is the form of disease 

 termed by the French traumatic aneurism, 

 the name having reference not so much to 

 the fact of its having been produced by 

 violence, as to the co-existence with it of a 

 solution of continuity in the skin and other 

 structures external to the vessel. Thus, although 

 an aneurism may be caused by the prick of a 

 lancet in the bend of the arm, or by a bayonet- 

 wound in the thigh, yet if the external wound 

 is healed, or, being unhealed, if it is so oblique 

 or devious that the blood flowing from the 

 artery does not escape from the limb, it may 

 not be called traumatic, whilst a common pop- 

 liteal aneurism that had arisen spontaneously, 

 if it is accidentally opened, assumes the cha- 

 racter just designated. The chief peculiarity 

 of this case, then, is the external wound, and if 

 it be conceded that it is the resistance of the 

 unyielding structures that presses the coagu- 

 lum against the vessel, and thus accomplishes 

 the cure of those forms of aneurism already 

 described, it will be seen that a material part 

 of the process must be deficient, and, therefore, 

 that the principles applicable to the former 

 cannot be made available here. 



In order to the proper understanding of this 

 part of the subject, it will be necessary to take 

 a familiar case for illustration. A person in 

 attempting to open a vein in the arm strikes 

 his lancet into the artery, and is, perhaps, 

 unconscious of the extent of the mischief he 

 has occasioned. The arm is tied up, but it 

 swells and becomes intolerably painful. When 

 the bandage is removed, the wound is found 

 not to have united, and a coagulum is pro- 

 bably seen plugging it up, which loosens occa- 

 sionally and allows the escape of a considerable 

 quantity of red and florid blood. In the 

 meantime the diffusion throughout the limb 

 is extending in every direction, and the hsemor- 



