38 ANATOMY OF VERTEBRATES. 



the e entogluteus,' fig. 12, f, the ' quadratus femoris,' the ' obturator 

 externus,' the * obturator internus,' the s gemelli,' and the ' pyra- 

 midalis ' — present a disposition similar to that which they have in 

 the human body. 



The muscles passing between the pelvis and the lesser tro- 

 chanter, and also those that arise from the pubis to be implanted 

 into the internal surface of the thigh, are the * psoas magnus,' the 

 * iliacus,' the ' pectinseus,' and the c triple adductor,' fig. 12, p. 



The flexor muscles of the leg are the ' biceps flexor cruris,' the 

 ' semimembranosus,' the ' semitendinosus,' the ' sartorius,' the 

 e gracilis,' and the 6 poplitaeus,' all of which are enclosed by the 

 dense fascia of the thigh, which is kept tense by the action of a 

 ' tensor vaginas femoris.' The last-named muscle, called also the 

 ' musculus fasciae lata?,' arises from the anterior portion of the 

 crest of the ilium, whence it descends obliquely downward, en- 

 closed between two layers of the fascia, covering the thigh, into 

 which it is strongly inserted. 



The extensor muscles of the leg — viz., the ( rectus,' fig. 11, h 9 

 the ' vastus internus,' fig. 12, 7, the 'vastus externus,' fig. 11, n, 

 and the ( cruraeus ' — offer in all quadrupeds the same general dis- 

 position as in Man, the three last forming one great common 

 muscle, 6 trifemoro-rotuleus.' The anterior margin of the thigh 

 is formed by the ( sartorius,' which here, from its position and 

 office, has been named by hippo tomists the ' long adductor of the 

 thigh.' 



The ( biceps cruris ' arises by a single origin, which is derived 

 from the ischium, and the neighbouring ligaments and fascial ex- 

 pansions. This muscle covers a large proportion of the outer 

 surface of the' thigh : its principal insertion is into the head of the 

 fibula, but it likewise throughout its whole length contracts ex- 

 tensive and important attachments with the fascia lata, so that it 

 also becomes a powerful extensor of the thigh. There is, how- 

 ever, a distinct portion of the biceps derived from the sacro- 

 sciatic aponeurosis, the fibres of which are directed obliquely from 

 before backward, which, meeting the ischiatic portion at an 

 angle, form with it a kind of raphe, which is prolonged for some 

 distance. This muscle is called ' vastus longus ' in Hippotomy. 

 The c gracilis,' fig. 12, u, is a very considerable muscle; it is 

 called by hippotomists the ' short adductor of the thigh,' whilst 

 they usually give the name 6 gracilis ' to the semitendinosus. 

 The ( semimembranosus ' and ( semitendinosus ' have the same 

 origin and general arrangement as in Man ; but both of them are 

 inserted into the tibia by a broad aponeurosis, extending much 



