114 ANATOMY OF THE DOMESTIC FOWL 



the semitendinosus. The inferior tendinous portion passes through 

 a tendinous sling or pulley called the biceps band. 



Action. Flexes the leg upon the thigh. 



Semitendinosus (Fig. 23, No. 10). Location. Posterior femoral 

 region. 



Origin. By a tough, strong fascia from the surface of the caudal 

 muscles and from the posterior third of the post-acetabular ridge. 



Insertion. The fibers pass downward and forward, and insert to 

 the tendinous raphe along the posterior margin of the semitendinosus 

 accessorius; lower down it merges with the median fascia of the 

 inner head of the gastrocnemius. 



Shape. Fleshy, broad, flat and long. 



Relations. Internally, with the semimembranosus and anteriorly, 

 with the biceps flexor cruris. 



Action. Flexes the leg. 



Semitendinosus Accessorius. Location. Posterior femoral region. 



Origin. From an oblique line just above the condyle, on the 

 posterior of the shaft of the femur. 



Insertion. Its fibers, passing upward and backward, attach them- 

 selves to the tendinous raphe common to this muscle and the semi- 

 tendinosus, and are finally inserted to the inner side of the shaft of 

 the tibia. 



Shape. Flat, oblong. 



Relations. Posteriorly to the shaft of the femur, and externally 

 to the long adductors of the thigh. 



Action. Aids the preceding in flexing the leg. 



Semimembranosus (Fig. 24, No. 17). Location. Postero-internal 

 to the semitendinosus. 



Origin. From the outer surface of the ischium, beginning at the 

 lower margin of its notch on the posterior pelvic border, extends on 

 a curved line on the adjacent surface beyond. 



Insertion. The fibers, passing downward and forward, insert by a 

 broad, thin tendon to the shaft of the tibia a short distance below 

 the head and on a line parallel to the long axis of the tibia. 



Shape. Long, narrow, ribbon-shaped. 



Relations. Lies adjacent to the semitendinosus and in the same 

 plane. 



Action. Directly flexes the leg. 



Femoro-caudal (Fig. 24, No. 8). Location. Infero-lateral to 

 the caudal and post-femoral region. 



