148 U.S. NATIONAL MUSEUM BULLETIN 2 73 



proximately 1 cm below the higher point of the adductor brevis 

 (fig. 40). 



Pars ischiocondyloideus should be treated with the postpelvic 

 group, but I include it here for topographical reasons. Its fibers of 

 origin are more superficial than those of the ischiofemoralis and have 

 a more direct association wath the tendon of the semimembranosus. 

 It descends along the medial side of the thigh and reaches the junction 

 of the medial epicondyle with the medial supracondylar fine, where 

 it is inserted (fig. 40). Some of its fibers are attached to the medial 

 head of the gastrocnemius. Sirena (1871) regards the ischiofemoralis 

 only as adductor magnus and calls the ischiocondyloideus m. adductor 

 quartus. 



Nerve supply: The ischiofemoraHs is supplied by the continuation 

 of the posterior ramus n. obturatorius and the ischiocondyloideus 

 by the same branch of the n. tibiahs that innervates the hamstring 

 muscles. 



Function: Adductor of the thigh. 



M. gracilis: This band-shaped muscle is the most superficial of 

 those on the medial side of the thigh. The gracilis, broader near origin 

 than at insertion, arises by strong fleshy fibers from (1) the public 

 crest in front of the insertion of the abdominal muscles, (2) the femoral 

 surface of the body of the pubis at the side of the symphysis, and (3) 

 a short stretch of the lower pubic ramus on its distal border (fig. 36). 

 A wide and flat belly is thus formed which descends along the medial 

 side of the thigh, covering the pectineus and the three adductors. 

 Midway between its origin and insertion, the graciHs has narrowed 

 considerably from its initial wide proportions. The muscle passes 

 dorsomedial to the knee where it is covered by the sartorius, with the 

 saphenous nerve and vessels intervening. Beyond this point the 

 gracilis is bound within a narrow aponeurotic compartment with the 

 underlying semitendinosus. It ends by fanning out into two orders of 

 fibers, which, nevertheless, form a single continuous sheet of insertion. 

 The proximal part is aponeurotic and the distal muscular (fig. 37). 

 This mixed attachment takes place behind that of the sartorius, with 

 the muscular part reaching further down along the tibia than the 

 sartorial fascicles (fig. 38). Sirena (1871) describes this insertion as 

 being common with that of the semitendinosus on the anterior tibial 

 crest and adds that the fasciae of these two muscles fuse distaUy and 

 descend down to the medial malleolus of the ankle. 



Nerve supply: The anterior branch of the obturator nerve sends 

 a large branch to the gracilis through the pectineus. 



Function: Flexor of the knee and adductor of the thigh. 



Comparative anatomy of the prepelvic coxofemoral group. — 

 This group of muscles in Ateles, Brachyteles, and Lagothrix has a strong 



