THE FEMORAL ARTERY. 82 



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Relations. — In its uppermost part, for a distance of about 3 cm. (i^ in.), the 

 femoral artery, together with the accompanying vein, is enclosed within a sheath 

 formed by a prolongation of the transversahs and iliac fasciae below Poupart's liga- 

 ment. T\\\~, femoral sheath is funnel-shaped and is divided by partitions into three 

 compartments, the most lateral of which contains the artery, the middle one the 

 femoral vein, while the medial one forms what is termed ih^/ejnoral or crural canal 

 (page 625). Below, the walls "of the sheath gradually pass over into the con- 

 nective tissue which invests the vessels. 



In the upper half of its course the femoral artery lies in Scarpa's triangle (page 

 639), while in its. lower half it is contained within a space known as Hunter'' s canal, 

 situated between the adductor magnus and vastus medialis muscles and covered in 

 by the sartorius. 



In Scarpa's triangle the relations of the artery are as follows. Anteriorly , it 

 is covered by the integument, the superficial fascia, and the fascia lata, the inner 

 margin of the attenuated portion of the latter fascia, which is known as the cribriform 

 fascia, overlapping it at about the junction of its upper and middle thirds. Superficial 

 to the fascia lata are some of the superficial inguinal lymphatic nodes and the superfi- 

 cial circumflex iliac vein, while deeper and resting upon the upper part of the artery is 

 the crural branch of the genito-crural nerve, and towards the apex of the triangle the 

 internal cutaneous nerve. Posteriorly, the artery rests upon the tendon of the ilio- 

 psoas muscle, which separates it from the capsule of the hip-joint, and lower down it 

 lies upon the pectineus muscle. Throughout the lower part of the triangle it is sep- 

 arated from the adductor longus muscle by the femoral vein and by the deep femoral 

 artery and vein. Medially, it is in relation above with the femoral vein and below 

 with the adductor longus; laterally, with the ilio-psoas muscle and the leash of 

 nerves formed from the anterior crural nerve. 



In Hunter's canal the artery lies beneath the sartorius muscle and is crossed 

 obliquely from without inward by the long saphenous nerve. Posteriorly it rests upon 

 the adductor longus and the adductor magnus, and also upon the femoral vein which, 

 below, comes to lie somewhat laterally as well as posterior to it and is firmly united 

 to the artery by dense connective tissue. To the inner side of the artery is the ad- 

 ductor longus above and the adductor magnus below, while to its outer side, and 

 partly overlapping it, is the vastus internus. 



Branches. — In Scarpa's triangle the femoral artery gives off (i) the super- 

 ficial epigastric, (2) the superficial circumflex iliac, (3) the superficial external 

 pudic, (4) the deep external pudic, (5) the profimda fiemotis, and (6) muscular 

 branches. In Hunter's canal it gives off additional muscular branches and, just 

 before perforating the adductor muscle, (7) the anastomotica viag7ia. 



The profunda femoris so much surpasses in size the other branches of the femoral 

 that the latter artery is frequently regarded as bifurcating at the point where th's 

 vessel arises. The portion of the artery above the bifurcation is then termed the 

 common femoral, while its continuation through Scarpa's triangle and Hunter's canal 

 is known as the superficial fieinoral. 



Variations. — A comparative study of the arteries of the thigh reveals the fact that the exist- 

 ence of a well-developed femoral artery forming the main blood-channel for the leg is a condi- 

 tion characteristic of the mammalia. In the lower vertebrate groups the sciatic is the principal 

 artery of the thigh, extending throughout the whole length of its flexor surface and becoming 

 continuous below with the popliteal artery, the femoral artery being comparatively insignificant 

 and terminating as the profunda femoris. The peculiar course of the mammalian femoral, start- 

 ing, as it does, as an artery of the extensor surface of the limb and later perforating the adductor 

 magnus to become continuous with the popliteal upon the flexor surface, is to be regarded, 

 therefore, as a secondary arrangement, and its history is somewhat as follows. 



While the sciatic is still the principal vessel of the thigh and retains its connection with the 

 popliteal below, a branch is given off from the femoral which accompanies the long saphenous 

 nerve through Hunter's canal and down the inner surface of the cms, having in this lower por- 

 tion of its course a superficial position corresponding with that of the nerve. Near the lower 

 part of Hunter's canal this vessel, which is known as the saphenous artery, gives off a branch 

 which perforates the adductor magnus and unites with the sciatic, producing an arrangement 

 which, in various degrees of development, may be regarded as characteristic of the mammalia 

 as a group. In man, however, the process goes a step further in that, correlatively with an 

 enlargement of the anastomosis between the saphenous and the sciatic, there is a diminution of 

 the main stem of the latter vessel, so that eventually it becomes reduced to the slender a. conies 



