36 



Turn aside or remove a portion of the obturator externus and trace the 

 respective branches suppHed to it and to the adductor magnus, the gracilis, 

 and pectineus to their respective places of origin from the obturator nerve. 

 It will now be seen that N. obturatorius divides into two branches one of 

 which is distributed to the gracilis and pectineus and the other to the 

 adductor magnus and obturator externus. 



N. pudendus (PI. V, 57, 57') originates from the 2d and 3d sacral nerves, or in 

 some cases from the 3d only. It extends posteriorly, at first on the inner or 

 pelvic surface of the sacro-sciatic ligament, but gradually passes into the 

 substance of the ligament. Near the lesser sciatic foramen the nerve 

 crosses the lateral surface of the A. pudenda interna, (PL V, 37), and 

 inclining inwards, turns around the ischial arch and gains the dorsal surface 

 of the penis along which it continues as the N. dorsalis penis. Shortly 

 before the nerve crosses the A. pudenda interna it gives off the N. haemor- 

 rhoidalis medius, or perinaeo-anal nerve (PL V. 57'') which is distributed 

 by numerous branches to the muscles of the urethra and penis, including 

 the ischio-cavernosus muscle, and to the terminal portion of the rectum. 

 The communicating branch of the posterior ventral gluteal nerve (PL V, 55) 

 to the N. pudendus joins the latter at the place of origin of the perinaeo-anal 

 nerve. In the female the N. pudendus is distributed to the labia, clitoris, 

 and the constrictor muscles of the vulva and anus and to the perineum. 



N, hemorrhoidalis (PL V, 60) is formed from the 3d and 4th sacral nerves 

 or from the 4th only. It passes posteriorly on the inner or pelvic face 

 of the sacro-sciatic ligament to the anal region where it divides into a 

 number of branches which are distributed to the retractor and sphinctor 

 muscles of the anus and to the skin of the perineal region. 



A. profunda femoris arises either in common with the truncus pudendo- 



epigastricus (or prepubic) or a little peripheral to it. It passes caudo- 

 ventrally between the pectineus and the terminal tendon of the iliacus 

 and psoas magnus. Draw aside the pectineus and demonstrate the one 

 or more small branches supplied to it. Beneath the adductor magnus the 

 artery gives off a very large branch which is distributed to this muscle, and 

 to the gracilis and the semimembranosus. It also supplies twigs to 

 the deep inguinal lymph gland.' The remaining portion of the A. profunda 

 femoris is covered by muscles and cannot be traced at present. A large 

 vein accompanies the artery. 



A. femoris anterior (PL V, 32) arises from the A. femoralis about 2 cm. peripheral 

 to the femoris profunda, from the opposite side of the A. femoralis. It passes 



