THE FEMORAL ARTERY. 821 



Variations.— The deep epigastric may arise from the external iHac higher up than usual, — 

 as high, indeed, as a point 6 cm. (2^ in.) above Poupart's Hgament. In such cases it passes 

 downward and forward upon the anterior surface of the external iliac to reach the abdominal 

 wall. It may also arise below its usual position, — that is to say, from the common femoral 

 artery, — and it may be given of? from a trunk common to it and the deep circumflex iliac. 



In addition to being frequently the origin of the obturator (page S14), it may be given of? 

 from that artery as a result of the enlargement of the anastomosis of the pubic branches of the 

 two arteries and the subsequent degeneration of the proximal portion of the deep epigastric. 

 Occasionally it gives origin to the dorsal artery of the penis or clitoris, an arrangement which 

 also results from its relation to the obturator, from which this artery sometimes arises. 



2. The Deep Circumflex Iliac Artery. — The deep circumflex iliac artery (a. 

 circumflexa ilium profunda) (Fig. 728) arises from the outer surface of the external 

 iliac, a little below the deep epigastric. It passes outward along the lower border 

 of Poupart's ligament, enclosed in a sheath formed by the iliac fascia, and opposite the 

 anterior superior spine of the ihum, or it may be a little beyond it, divides into an 

 ascending and a horizontal branch. 



Branches. — In its course it gives branches to the muscles of the abdominal wall and, at 

 the anterior superior spine of the ilium, to the upper part of the sartorius and to the tensor 

 vaginae femoris. , 



(a) The ascending branch pierces the transversalis muscle and ascends directly upward 

 between that muscle and the internal oblique. It sends branches to both these muscles, as well 

 as to the external oblique and the integument, and terminates by anastomosing with the lumbar 

 arteries and with the tenth aortic intercostal (subcostal). 



{d) The horizontal branch continues the course of the main stem. It lies at first a little 

 below the crest of the ilium, but later ascends and perforates the transversalis muscle, passing 

 onward upon the crest of the ilium between that muscle and the internal oblique. It gives off 

 branches which supply the abdominal muscles and anastomose with the lumbar arteries, and 

 terminates by anastomosing with the lumbar branches of the ilio-lumbar. 



Variations. — The deep circumflex iliac artery may arise from a common stem with the deep 

 epigastric or from the upper part of the common femoral artery. Not infrequently it gives rise 

 to a branch, shortly after its origin, which passes upward upon the anterior abdominal wall, un- 

 derneath the transversalis fascia, parallel and lateral to the deep epigastric. This lateral epi- 

 gastric artery, as it has been termed, is occasionally of considerable size, in which case the 

 ascending branch of the circumflex iliac may be more or less reduced. It may ascend to the 

 level of the umbilicus or even above that point, sending branches to the muscles of the abdom- 

 inal wall 



Anastomoses of the External Iliac. — Opportunities for the development of 

 a collateral circulation after ligation of the external iliac artery are afforded by the 

 anastomoses of its deep epigastric branch with the superior epigastric branch of the 

 internal mammary, with the lower aortic intercostals, and with the lumbar arteries. 

 The deep circumflex iliac also makes connections with the lumbar arteries by its 

 ascending and lateral epigastric branches, and, furthermore, anastomoses with the 

 ilio-lumbar and gluteal branches of the internal iliac. Another connection with the 

 internal iliac system is made by the anastomoses of the pubic branches of the deep 

 epigastric and obturator arteries. 



Anastomoses between branches of the internal iliac and the femoral arteries are 

 also of importance in this connection, but will be described in connection with the 

 femoral artery (page 831). 



THE FEMORAL ARTERY. 



The femoral artery (a. femoralis') (Figs. 729, 732) is the continuation of the 

 external iliac below Poupart's ligament. Its course is almost vertically downward, 

 with a slight inclination inward and backward, and may be indicated by a line drawn 

 from a point in Poupart's ligament midway between the symphysis pubis and the 

 anterior superior spine of the ilium to the adductor tubercle upon the inner condyle 

 of the femur, when the thigh is flexed upon the pelvis and rotated outward. It ter- 

 minates at about the junction of the middle and lower thirds of the thigh, where it 

 passes through the adductor magnus muscle, close to the inner surface of the femur, 

 to become the popliteal artery. 



