230 



ARTERY, PATHOLOGICAL CONDITIONS OF. 



there is the same effusion of lymph, the for- 

 mation of internal coagulum of the same conical 

 shape and to the same extent, the diversion of 

 the circulation through the collateral branches, 

 and if the case proceeds favorably, the ultimate 

 obliteration of the tube between the place 

 occupied by the ligature and the next anasto- 

 mosing branch. But the ligature is still to be 

 attended to. The portion of the cellular coat 

 included within its noose sloughs and dies, 

 and is to be detached from the remainder 

 by the absorption of the adjacent sound part. 

 This process takes place at different periods of 

 time according to the size of the vessel ; it 

 separates from the subclavian about the twenty- 

 second day after the operation, from the femoral 

 about the sixteenth, and from the brachial so 

 early as the twelfth or fourteenth. Unfor- 

 tunately matters do not always proceed thus 

 favorably, and the separation of the ligature is 

 the commencement of a series of evils to the 

 patient and of embarrassment to the surgeon, 

 that can scarcely be paralleled in the practice 

 of surgery. It has been found, however, by 

 experience, that a ligature placed on an artery 

 that has been fairly divided, is more rarely 

 followed by those ill consequences that fre- 

 quently ensue when its continuous tube is tied, 

 and as this latter operation is so intimately 

 connected with the subject of aneurism, and as 

 it will be necessary to become acquainted with 

 the phenomena of inflammation in these struc- 

 tures, in order to understand those of secon- 

 dary or consecutive haemorrhage, this part of 

 the subject cannot at present be so favorably 

 discussed. 



Morbid states of arteries. Aneurism. 

 Aneurism (ayy^crjw.o?, vel otvsv^vt7[^o<;,') is a 

 term of such extensive application as to pre- 

 clude the possibility of an accurate definition. 

 It has been employed by Corvisart and others 

 to designate certain affections of the heart, but 

 is now most generally used to express a disease 

 produced by a dilatation of an artery, or by 

 solution of continuity in one or all of its coats. 

 It is also applied to any distended condition of a 

 part of the vascular system, such as occurs when 

 an unnatural communication is formed between 

 an artery and vein, constituting the diseases of 

 aneurismal varix and varicose aneurism. The 

 name of aneurism by anastomosis has also 

 been given to those bloody tumours, which, at 

 first appearing only as marks or stains occa- 

 sioned by a congeries of vessels, increase either 

 with the growth of the individual, or according 

 as the vascular system may be accidentally ex- 

 cited, until finally they produce results of a 

 most formidable description. 



Aneurisms have been classed, first, as to the 

 condition of the coats of the artery, a dilata- 

 tion of them being considered as the true aneu- 

 rism, whilst a rupture or ulceration of them 

 constitutes the false : and, secondly, as to the 

 condition of the effused blood, which, if it is 

 contained within a sac or bag, constitutes the 

 circumscribed [form of the disease, or if it has 

 been poured out throughout the circumjacent 

 cellular tissue, forms the diffused aneurism. 

 The nature of aneurism, however, will be better 



understood by considering it to consist of such 

 a lesion of an artery as will permit the passage 

 of a portion of the blood out of the usual course 

 of the circulation, though not out of the vicinity 

 of the injured or diseased vessel, and according 

 to the different circumstances under which this 

 can occur, the disease will be found to arrange 

 it-elf under the following distinct species. In 

 the first four of these the effused blood is either 

 partially or entirely withdrawn from the circu- 

 lation, and becomes coagulated in its new 

 situation : in the others it passes from the usual 

 course of the circulation, but is not withdrawn 

 entirely from it, and consequently does not 

 coagulate. 



1. Where by rupture or ulceration of the 

 internal and middle coats of the vessel, the 

 blood is propelled against the external cellular 

 coat, which becomes thus distended into a pouch 

 containing within it the extravasated blood, in 

 a more or less perfect state of coagulation, 

 which pouch is termed the aneurismal sac. 

 This is circumscribed false aneurism. 



2. The true aneurism is when all the coats 

 of an artery, in one particular part of its cir- 

 cumference, are so far deprived of their elastic 

 properties as to yield, become distended, and 

 form a pouch, in which the contained blood is 

 similarly circumstanced. 



3. It is not difficult to conceive that the sac 

 of a true aneurism, as just described, will not 

 long endure its state of unnatural distension 

 before its internal and fibrous coats either ulce- 

 rate or rupture, and then an aneurismal sac is 

 formed, consisting in one part of all the coats 

 of the dilated vessel, and in the other of the 

 cellular tunic alone. This is obviously a mixed 

 form of aneurism. 



4. When there is a wound, rupture, or 

 ulceration of all the coats of an artery, in such 

 wise as to permit the escape of the blood into 

 the adjacent cellular tissue, a diffused aneurism 

 is formed. This, for reasons that need not 

 explanation, will be most frequently observed 

 to succeed to wounds or punctures of vessels, 

 but it may also be the consequence of an acci- 

 dental rupture of the sac of a circumscribed 

 aneurism allowing the blood to pass through 

 it, and spread itself (as it generally does) in 

 every direction throughout the loose cellular 

 tissue of the entire limb. 



5. A direct and immediate communication 

 may be established between an artery and a 

 vein lying close upon it, as by the passage of a 

 lancet transfixing one vessel and entering the 

 other. This is the aneurismal varix, obviously 

 occurring with greater frequency as the result 

 of a wound, but nevertheless occasionally seen 

 as the product of disease. 



6. A small circumscribed aneurismal sac 

 has been found situated between an artery and 

 vein so transfixed, communicating with both, 

 and permitting a transmission of blood from 

 one vessel into the other. This variety has 

 been named the varicose aneurism. 



7. A portion of blood may be contained 

 within a new arid diseased formation of cellu- 

 lar structure, the precise nature of which is 

 not understood. The trunks of the arteries in 



