The Posterior Limb. 



147 



(c) The vastus intermedius. Origin in two portions: 



First portion: Great trochanter, below the origin of the 



vastus lateralis. 



Second portion: Anterior surface of the femur. 



(d) The vastus medialis. Origin: Medially, at the base of the 

 collum fcmoris and adjacent portion of the shaft. 

 Common insertion (a-d) : Tibial tuberosity. 



B. Flexor group (hamstring ^^^^^^^ 



muscles). With the exception of 

 the sartorius, the muscles lie behind 

 the axis of the femur, and are in- 

 serted on the medial and lateral 

 surfaces of the knee-joint and the 

 corresponding proximal portions of 

 the leg. They form the bound- 

 aries of the popliteal fossa. 



(a) The sartorius. Origin: 

 Posterior portion of the 

 inguinal ligament, espe- 

 cially its sacral exten- 

 sion. Insertion: Medial 

 condyle of the tibia. 

 This is an extremely 

 thin and narrow band 

 of fibres, lying on the 

 more anterior portion 

 of the medial surface of 

 the thigh. The muscle 

 is fused distally with 

 the gracilis. It has the 

 position of a rotator 

 muscle, and is onlv a 

 flexor through its con- 

 nection with the latter. 



(b) The gracilis. Origin : 

 The entire extent of 

 the pubic symphysis. 

 Insertion: Through a 

 broad tendinous expan- 

 sion ending in the fascia 

 of the proximal portion 

 of the medial surface of 

 the thigh. The muscle 

 forms a broad, comparatively thin sheet, covering the pos- 

 terior portion of the medial surface of the thigh. Its inser- 

 tion tendon is perforated by the great saphenous artery and 

 vein and the greater saphenous nerve. 



The sartorius and gracilis should be raised from the surface and 

 divided. 



Posterior 



Fig. 48. Transverse section through the middle 

 of the thigh: a.l., adductor longus; a.m., ad- 

 ductor magnus; b.f.l and b.f. 2, first and second 

 heads of the biceps femoris; f., femur; gr., 

 gracilis; n.p., peroneal nerve; n.s.ni., greater 

 saphenous nerve; n.t., tibial nerve; r.f. 1 and 

 r.f. 2, first and second heads of the rectus fenioris; 

 s., sartorius; sm., semimembranosus; st., semi- 

 tendinosus; t.f.c, tensor fasciae crtiris; t.f.l., 

 tensor fasciae latae; v.i, 1 and v.i. 2, first and 

 second heads of the vastus intermedius; v. is., 

 sciatic vein; v.i., vastus lateralis; v.m., vastus 

 medialis; v.s.m., great saphenous vein. 



