Operative relations of the femoral artery.— The femoral artery may be the subject of ope ration at any part of its course, there being nothing either in its situation or relations to forbid the exposure of it at any point, if cir cumstances should require it. All parts, how ever, are not equally eligible, the vessel being in some situations more deeply situate, covered by a greater number and depth of parts, and its relations more complicated than at others. It has been taken up in each of the three stages into which its course has been divided, and the operations, which may according to circumstances be performed upon it, may with advantage be referred to those. The propriety of thus distinguishing them will appear in a strong light, when those modifications, which the anatomical relations of the vessel may justify, shall have been discussed, as also from the history of the operations, which have been and are proposed to be performed upon the femoral artery.
In its first stage the vessel may be tied at two points, viz. either above or below the origin of the profunda artery : the operation at the former point, being performed under circumstances different from those in which that at the latter is admissible, may be con sidered apart from the others, and the de tail of it be postponed until they have been disposed of; while the operation in the second case, and those in the second and third stages have been at different times performed for the same purpose—the cure of popliteal aneurism —and therefore a comparison of their several details and advantages merits attention. The situation in which the femoral artery was first taken up for popliteal aneurism is the third stage of its course: here it was tied, as is generally known, by J. Hunter. In his ope ration Hunter made " an incision on the an terior and inner part of the thigh rather below its middle ;" i.e. in the third stage ; " which in cision was continued obliquely across the inner edge of the sartorius muscle and made large:" the other steps of his operation it is not neces sary at present to particularize ; the author would only remark, as a matter of history, that Hunter's application of ligatures has been mis understood : he applied in his first operation four ligatures to the artery, and it is com monly, if not generally, said that they were drawn with various degrees of tightness ; but such was not the case, they were tied all equally tight : the account given in the report of the operation being, " the artery was now tied by both these ligatures," viz, the two upper, " but so slightly as only to compress the sides together. A similar application of ligatures was made a little lower. The reason for hav ing four ligatures was to compress such a length of artery, as might make up for the want of tightness, it being wished to avoid great pressure on the vessel at any one part." The artery may be and has been frequently taken up in the middle stage, and the ope ration, as described in several surgical works, will be found to belong to, if not to be in tended for, that stage. During its two latter stages the artery is covered by the sartorius: in its uppermost it is not covered by the muscle, and consequently if it be necessary to displace the muscle to bring the artery into view above the last stage, it must be in the middle one, and in the account of the operation given by some of the highest authorities, the displace ment of the sartorius is stated as one of the steps. This the author refers to not in a spirit of criticism, but in order to mark more strongly the distinction between the operations at the several stages, and to direct attention to the advantages possessed by that in the first over the others; more particularly since de scriptions, which in strictness apply to the operation in the middle stage, and at a part of the aitery's course below the first, may be found so put forward that the operations at the two points must be confounded; and thus the advantages contemplated by the proposer of the latter be lost. It will be recollected that in the two inferior stages the artery is covered by the sartorius and by two lamina: of the fascia lata, between which the muscle is situate : the vessel is, therefore, similarly cir cumstanced in this particular throughout both, but in some other important respects the re lations of the artery are different. 1. In its middle stage the vessel is nearer to the anterior plane of thelimb. 2. The deep layer of fascia, by which it is covered, is far less thick and strong, particularly at its upper part. 3. The artery is not so completely covered by the sar torius ; and for those reasons the vessel may be more easily reached from before. These constitute the principal anatomical conside rations why the middle stage should be pre ferred to the lower for operation, but, since it is at times requisite to tie the vessel in its last stage, it is necessary to examine the influence which its anatomical relations may have upon the conduct of the operation at that part.
1. The greater depth of the artery from the anterior surface of the limb renders a more extended incision necessary : in cutting upon arteries " the centre of the incision should be," as directed by Guthrie, " if possible directly over that part of the artery on which it is in tended to apply the ligature." In the case of the femoral artery in its third stage, the length of the incision should not be less than from four to five inches according to the volume of the limb ; its direction should correspond to that of the sartorius, but it must be varied somewhat according to the side of the muscle upon which the operator may purpose to seek the vessel. It should commence somewhat below the middle of the thigh, and be con tinued as much upon the lower as upon the middle third of the limb. 2. The artery is situate, in its third stage, nearer to the outer than the inner margin of the sartorius, and the more so the nearer to its termination; hence it may be exposed with greater ease and cer tainty by cutting upon the outer edge of the muscle and displacing it inward. Ilunter, in his operations, selected the inner margin, and displaced it forward and outward; but this proceeding is attended with disadvantages. 1. The saphena vein is more in the way and exposed to danger of being divided since it lies at this part, along or near the inner mar gin of the sartorius. 2. The muscle lying more to the inner than the outer side of the artery must be more displaced, and the depth of the wound for the same reason greater when the vessel is sought from its inside.* 3. The ope ration must be more inconvenient and em barrassing, as well because of the former difficulties as because it must be performed more from the inside of the limb, and from within outward, than in the method by the outer margin of the sartorius. Those objec tions are avoided by cutting upon the outer edge of the muscle, against which, however, it has been advanced that in that method the vastus intemus may be mistaken for the sar torius, and that the wound being made from before, there is not a depending and ready outlet afforded to matter should it form, while by the other there is. The former of these objections cannot carry much weight, and for the second the best plan for obviating the dangers of inflammation and suppuration is, as much as possible, to render them unneces sary, which is best accomplished by selecting that method by which the artery may be ex posed most easily, and with least disturbance to the parts in its vicinity. To the writer, therefore, it seems that the method by the outer margin of the sartorius, which appears to have been suggested by Hutchison, is the more eligible in the operation for taking up the femoral in its third stage. 2. The great thickness and strength of the anterior wall of the femoral canal both increase the dif ficulty of opening the canal, and render it desirable that that structure should he freely divided for the double purpose of facilitating the taking up of the artery, and preventing the injurious effect which must be produced by the confinement caused by the structure in question in the event of inflammation extend ing along the vessel. 3. The relation of the vein to the artery at this part, viz. posterior and external, will make it more safe to pass the needle round the latter from without than from the outside ; this, however, is a rule which cannot be strictly adhered to, for the direction in which the instrument shall be passed must be varied according to circum stances; it would be difficult to pass it from the outside in case the artery were exposed from the inside of the sartorius; but attention to the caution demanded by the position of the vein is,' for this reason, only the more necessary. 4. The saphenus nerve being here within the femoral canal is to be carefully avoided ; it will be so with certainty, if the needle be carried from the outside. 5. The mistake of confounding the superficial supe rior internal articular artery with the femoral must be also avoided.* This mistake, which has occurred, ought not however to occur again in the hands of a well-informed surgeon, for the possibility of it ought not to be lost sight of in operations at the lower part of the thigh; and it may be easily avoided by re collecting, first, that the femoral itself is within the femoral canal, and therefore that any vessel, which presents before the division of the anterior wall of the canal, which is so remarkably thick in this situation that it can hardly be overlooked, cannot be the one which is sought for; and, secondly, that the course of the branch within the canal, after its origin, is very short, and therefore that in case of doubt the vessel which presents, must, if the arti cular, conduct us directly to the trunk itself, when followed upward for a very short dis tance.