The depth, therefore, of the femoral artery from the surface, .and the number of coverings which it may have in individual cases, must be materially influenced by those several con ditions of the subcutaneous cellular structure when present, and they should never be lost sight of; else uncertainty and embarrassment must arise in the conduct of operations. It is further to be borne in mind that the account of the coverings of the artery given in this description has reference to the natural and most simple arrangement of those structures. The subcutaneous structure also encloses within it the superficial vessels, nerves, and glands, the relation of some of which to the artery requires notice. The superficial vessels are the saphena vein, the superficial femoral veins, and those veins and arteries by which the inguinal glands are supplied.
The saphena vein ascends, from the inner and back part of the knee, along the inner and an terior aspects of the thigh to its upper extre mity, where it joins the femoral vein upon its anterior and internal side, at the distance of from one inch to an inch and a half below Poupart's ligament. During its ascent the vein passes forward and outward, and is situate internal to the femoral artery : at the lower extremity of the middle third of the thigh, (the point at which the artery is about to pass into the ham,) it is placed superficial to the vessel, between it and the internal surface of the limb, near to the inner, or at this part the posterior margin of the sartorius muscle; but as the vein ascends, the distance between the vessels increases, partly because of the greater width of the thigh at its upper part, and partly because the course of the vein describes a curve convex inward ; and at the termination of the hitter it amounts to the width of the femoral vein or somewhat more; lower down it is still greater in consequence of the curve formed by the saphena. Hence, in operations upon the superior part of the artery, the saphena ought to be exempt from danger ; while at the lower part it must be very much exposed, if the inner margin of the sartorius be cut upon as the guide to the vessel.
The superficial femoral veins next claim attention : they are very irregular in their course and destination, and therefore are the more likely to prove a source of embarrass ment in operation. They are smaller than the saphena, but yet are in many cases of con siderable size : they present, according to the subject, two dispositions; either they join the saphena during its ascent at variable points in the course of the thigh, and in such case cross the limb and the artery obliquely from without inward, at different heights ; or they form one or two considerable vessels, which ascend external to the saphena, and open into the femoral vein in front, at the same time with the former vessel, passing through the superficial lamina of the fascia lata in the same manner as it does. When there are
two such veins, the inner one is generally situate internal to the artery, between it and the saphena, and consequently very near to it; while the external one, or the vein, if there be but one, runs upward and inward, and crosses the artery in its upper third, between the point at which the saphena joins the femoral vein and that at which the artery is overlapped by the sartorius : the last-de scribed vein, when present, must obviously be much endangered in exposing the femoral artery at this part of its course, and perhaps is the vessel which has given rise to the idea that the saphena itself may be encountered in cutting upon the artery in this situation.
The superficial inguinal glands are distin guished into two sets, a superior and an in ferior: those of the former are more numerous, and nearer to the integuments than the latter. They are ranged immediately below Poupart's ligament, having their longer diameter parallel to it, and in greatest number superficial to that part of the iliac portion of the fascia lata, which is called its cribriform portion, and over the course of the femoral artery, across which they are placed obliquely : they are separated from the vessel by the superficial lamina of the iliac portion of the fascia, and by the prolongation of the fascia transversalis, with the interposed cellular structure ; and they derive numerous arterial and venous branches from the main trunks beneath : those branches, which are given off partly by the vessels themselves, and partly by their super ficial pudic, superficial epigastrie, and su perficial anterior iliac branches, pass through the interposed structures in order to reach the glands; in doing so they carry with them sheaths from the fascia lata, which is prolonged upon each as it escapes, and thus they become the means of establishing that connection be tween the fascia in the groin and the subcu taneous stratum, in which the glands are enveloped, which is considered to influence so remarkably the course of femoral hernia. The glands of the second set are less nu merous, are situate farther from Poupart's ligament than the former, being below the entrance of the saphena ; they are also deeper seated, lying upon the fascia lam, and they are placed with their longer diameter parallel, or nearly so, to the femur and to the course of the artery. Their relation to the artery is not in all cases the same, inasmuch as the disposition of neither part is strictly uniform, but usually one or two of them lie over the vessel, or immediately on either side of its course; their relation to it, however, is, in the natural condition of the parts, not of great consequence; for in such ease they may be easily held aside during operation if necessary, and thus both they and their lymphatic vessels be saved from injury.