THE MUSCLES. 175 



time thigh and leg (in squatting) or both alone. It only slightly 

 assists in crossing the legs (the position of tailors when at work). 

 Nerves: cruralis. 



355. 6. Extensor cruris. 



Or. : see a. to d. Ins. : the tendinous expansion around the 

 patella; tendo extenso cruris. Use: to extend the leg or thigh 

 (when the one or the other is fixed, as in rising from the sitting 

 to the standing posture). 



[REMARK. To examine the insertion accurately, make a vertical section of 

 the tendon, patella, and ligam. patella in the centre. TRANS.] 



a. Rectusfemoris. 



Pos. : vertical in the centre of the thigh, between Spina ilei 

 anter. super, and patella; above rather covered by Sartorius, in 

 general by the skin. Covers above the flexor, below the three 

 following muscles. Or. : from superior border of acetabulum; 

 from Spina ilei anter. infer. 



b. Vastus externus. 



Pos. : behind the last, externally covered by skin, before cru- 

 ralis. Or. : tro chanter-major and labium externum linese asperx 

 (superior half). 



c. Vastus internus. 



Pos.: on the inner part of the thigh, grooved; behind, the 

 inferior extremities of the adductores lie upon it. Or. : from 

 labium intern, lin. asperse, before m. adductores (from tro- 

 chanter minor) as far as the inferior fourth of the thigh. 



d. Cruralis. 



Pos.: close upon osfemoris, surrounded as if in a capsule by 

 vastus externus and internus. Or. : os femor., close under 

 vastus intern., as far as above condylus intern, femoris. The 

 lowest fasciculi have been named Subcruralis. 



Nerves of extensor fern. : cruralis (for vast, intern.), besides, nerv. obturatorius. 



d. Internal surface. 



356. 7. Gracilis. 



Pos. : close under the skin, directly downwards ; covers the 

 adductores, below semitendinos.; at the inferior extremity of the 

 internal surface crossed by Ven. saphena interna. Or.: from 

 Spina pubis ram. ascend, oss. ischii. Ins.: Crista tibiae (within 

 and above), below tendo Sartorii and above tend, semitendinosi. 



