630 THE ARTERIES. 



Peculiarities. The origin of the epigastric may take place from any part of the external 

 iliac between Poupart's ligament and two inches and a half above it, or it may arise below this 

 ligament, from the femoral or from the deep femoral. 



Union with Branches. It frequently arises from the external iliac by a common trunk 

 with the obturator. Sometimes the epigastric arises from the obturator, the latter vessel being 

 furnished by the internal iliac, or the epigastric may be formed of two branches, one derived 

 from the external iliac, the other from the internal iliac. 



Surgical Anatomy. The deep epigastric artery follows a line drawn from the middle of 

 Poupart's ligament toward the umbilicus; but shortly after this line crosses thelineasemilunaris 

 the direction changes, and the course of the vessel is directly upward in the line of junction of 

 the inner third with the outer two-thirds of the Rectus muscle. It has important surgical 

 relations, in addition to the fact that it is one of the principal means, through its anastomosis 

 with the internal mammary, in establishing the collateral circulation after ligature of either the 

 common or external iliac arteries. It lies close to the internal abdominal ring, and is therefore 

 internal, to an oblique inguinal hernia, but external to a direct inguinal hernia, as it emerges 

 from the abdomen. It forms the outer boundary of Hesselbach s triangle. It is in close rela- 

 tionship with the spermatic cord, which lies in front of it in the inguinal canal, separated only 

 by the transversalis fascia. The vas deferens hooks round its outer side. 



The Deep Circumflex Iliac Artery arises from the outer side of the external 

 iliac nearly opposite the epigastric artery. It ascends obliquely outward behind 

 Poupart's ligament, contained in a fibrous sheath formed by the junction of the 

 transversalis and iliac fasciae, to the anterior superior spinous process of the ilium. 

 It then runs along the inner surface of the crest of the ilium to about its middle, 

 where it pierces the Transversalis, and runs backward between that muscle and 

 the Internal oblique, to anastomose with the ilio-lumbar and gluteal arteries. 

 Opposite the anterior superior spine of the ilium it gives off a large branch, which 

 ascends between the Internal oblique and Transversalis muscles, supplying them, 

 and anastomosing with the lumbar and epigastric arteries. 



AETERIES OF THE LOWER EXTREMITY. 

 The Femoral Artery (Fig. 376). 



The femoral artery is the continuation of the external iliac. It commences 

 immediately behind Poupart's ligament, midway between the anterior superior 

 spine of the ilium and the symphysis pubis, and, passing down the fore part and 

 inner side of the thigh, terminates at the opening in the Adductor magnus, at the 

 junction of the middle with the lower third of the thigh, where it becomes the 

 popliteal artery. The vessel, at the upper part of thigh, lies a little internal to 

 the head of the femur ; in the lower part of its course, on the inner side of the 

 shaft of the bone, and between these two parts the vessel is far away from the bone. 

 In the upper third of the thigh it is contained in a triangular space called Scarpa's 

 triangle. In the middle third of the thigh it is contained in an aponeurotic canal 

 called Hunter's canal. 



Scarpa's Triangle. Scarpa's triangle corresponds to the depression seen 

 immediately below the fold of the groin. It is a triangular space, the apex of 

 which is directed downward, and the sides formed externally by the Sartorius, 

 internally by the Adductor longus, and above by Poupart's ligament. The floor of 

 the space is formed from without inward by the Iliacus, Psoas, Pectineus, a small 

 part of the Adductor brevis and the Adductor longus muscles ; and it is divided 

 into two nearly equal parts by the femoral vessels, which extend from the middle of 

 its base to its apex, the artery giving off in this situation its cutaneous and 

 profunda branches, the vein receiving the deep femoral and internal saphenous. 

 On the outer side of the femoral artery is the anterior crural nerve dividing into 

 its branches. Besides the vessels and nerves, this space contains some fat and 

 lymphatics. 



Hunter's Canal. This is the aponeurotic space in the middle third of the 

 thigh, extending from the apex of Scarpa's triangle to the femoral opening in the 

 Adductor magnus muscle. It is bounded, externally, by the Vastus internus ; 

 postero-internally by the Adductor longus and magnus ; and antero-internally by 

 a strong aponeurosis which extends transversely from the Vastus internus, across 



