572 THE BLOOD-VASCULAR SYSTEM. 



other coverings of the cord, anastomosing with the spermatic artery ; a pubic 

 branch, which runs along Poupart's ligament, and then descends behind the os 

 pubis to the inner side of the femoral ring, and anastomoses with offsets from the 

 obturator artery ; muscular branches, some of which are distributed to the abdom- 

 inal muscles and peritoneum, anastomosing with the lumbar and circumflex iliac 

 arteries ; others perforate the tendon of the External oblique, and supply the 

 integument, anastomosing with branches of the superficial epigastric. 



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 common 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 the linea semilunaris 

 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. 



ARTERIES OF THE LOWER EXTREMITY. 



The artery which supplies the greater part of the lower extremity is the direct 

 continuation of the external iliac. It continues as a single trunk from Poupart's 

 ligament to the lower border of the Popliteus muscle, and here divides into two 

 branches, the anterior and posterior tibial, an arrangement exactly similar to what 

 occurs in the upper limb. For convenience of description, the upper part of the 

 main trunk is named femoral, the lower part, popliteal. 



The Femoral Artery (Fig. 317). 



The femoral artery commences immediately behind Poupart's ligament, midway 

 between the anterior superior spine of the ilium and the symphysis pubis, and, pass- 

 ing 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 the thigh, 

 lies in front of the hip-joint, just on a line with the innermost part of the head of 

 the femur ; in the lower part of its course it is in close relation with the inner side 

 of the shaft of the bone, and between these two parts the vessel is some distance 

 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 inner margin of the Adductor longus, and above by Poupart's 



