THE MUSCLES ON THE POSTEEIOK ASPECT OF THE THIGH. 419 



distance of two or three inches with the semitendinosus, forms a separate fleshy 

 mass, which extends to the distal third of the thigh, to end in a tendon joined by 

 the short head of the muscle. (2) The short head arises separately from, (1) the 

 whole length of the lateral lip of the linea aspera and the proximal two-thirds 

 of the lateral epicondylic line of the femur, and (2) the lateral intermuscular 

 septum. The proximal limit of its origin is sometimes blended with the insertion 

 of the lowest fibres of the glutseus maximus. 



The fibres of the short head, directed distally, join the tendon of the long 

 head, and the muscle is inserted (1) into the head of the fibula by a strong tendon, 

 which is split into two parts by the fibular collateral ligament of the knee-joint ; 

 (2) by a slip attached to the lateral condyle of the tibia ; and (3) along its posterior 

 border by a fascial expansion which connects the tendon with the popliteal fascia. 



, Obliquus externus abdominis 

 (insertion) 



Glutteus maximus 

 (origin) 



Rectus femoris (reflected 

 head of origin) 



Gemellus superior (origin) 



Gemellus inferior (origin) 



Semimembranosus (origin) 



Biceps and semitendinosus (origin) 



Quadratus femoris (origin) 

 Obturator externus (origin) 

 Adductor magnus (origin) 



Adductor magnus (origin) 

 FIG. 374. MUSCLE- ATTACHMENTS TO THE RIGHT DORSUM ILII AND TUBER ISCHIADICUM. 



There is a bursa between the tendon and the fibular collateral ligament of the 

 knee-joint. 



The short head may be absent : there may be an additional origin from the 

 ischium or femur ; and the long head may send a slip to the gastrocnemius or tendo 

 calcaneus (Achillis) (tensor fasciae suralis). 



M. Semitendinosus. The semitendinosus arises, in common with the long 

 head of the biceps, from the inferior and medial facet upon the ischial tuberosity 

 (Fig. 374, p. 419). Separating from the common tendon, two or three inches 

 from its origin, the muscle forms a long, narrow band which becomes tendinous 

 in the middle third of the thigh. 



Passing over the medial side of the knee it spreads out and becomes membranous, 

 and is inserted (1) into the medial side of the body of the tibia just distal to 

 the medial condyle, distal to the gracilis and behind the sartorius (Fig. 3*76, 

 p. 420), and (2) into the deep fascia of the leg. A bursa separates it from the 

 sartorius superficially, and another, common to it and the gracilis, lies deep to its 

 insertion. The belly of the muscle is marked by an oblique septal tendinous 

 intersection about its middle. 



