THE FROG 11 



arising from the scapula, the mediate, laterale, and profundum 

 from the humerus). All unite to give rise to a tendon which 

 passes over the elbow-joint to be inserted on the ulno- 

 radius. 



The muscles of the forearm and hand are more numerous and 

 may be grouped as flexors and extensors accordingly as they bend 

 or straighten the parts. 



In the dorsal view of the hind limb make out the following 

 muscles. The iliacus externus, extending from the outer side of 

 the ileum to the trochanter of the femur. The pyriformis, extend- 

 ing from the tip of the urostyle to the crista femoris. The 

 triceps femoris, on the outside of the limb, which arises from the 

 girdle by three heads: a, the glutasus maximus (vastus externus), 

 most posterior on the dorsal surface, from the posterior end of 

 the ileum between the iliacus externus and the pyriformis; b, the 

 caput medium (rectus femoris anticus), passes below the external 

 iliac to its origin from the ventral surface of the ileum; c, the 

 cruralis (vastus externus), not visible from above. All divisions 

 unite in a broad tendon inserted on the distal end of the femur 

 and the proximal end of the tibio-fibula. 



Medial to the distal end of the triceps the posterior part of 

 the ileo fibularis muscle can be seen. Its origin from the hinder 

 end of the ileum is concealed beneath the glutaeus maximus. Its 

 tendon passes over the knee and is inserted on both femur and 

 the upper fibular portion of the os cruris. 



Next nearer the median line is the large semimembranosus 

 muscle, crossed by an oblique inscriptio tendinea. It arises 

 from the ischiopubic region of the pelvis and is inserted on the 

 proximal end of the os cruris. 



The gracilis minor lies on the medial side of the limb. It 

 arises, with its fellow of the opposite side, from a tendon in the 

 middle line, just ventral to the anus, and unites distally with the 

 gracilis major (infra). 



Sketch these superficial dorsal muscles of the thigh. 



On the ventral surface of the thigh recognize the median head 

 of the triceps femoris and also the gracilis minor. Also see the 

 cruralis head of the triceps which arises from the wall of the ace- 

 tabulum (its origin will be seen later). 



A flat muscle, the sartorius, crosses the proximal end of the 

 cruralis and extends along the nrdventral surface of the thigh 



