286 ANATOMY OF THE DOMESTIC FOWL 



section of the crural nerves pass in a distal direction over the inner 

 and front side of the cutaneous nerve and enter the ilio-femoralis, 

 or gluteus medius, the ambiens and the femoro-tibialis muscle. 



The furcalis nerve comes out between the lasttwo lumbo-sacral 

 vertebrae. 



The obturator nerve springs from several roots. The anterior root 

 of this nerve comes from the main trunk of the crural plexus, and 

 its last root from the furcalis nerve. The obturator nerve extends 

 in a ventral direction from the plexus, then horizontally on the inner 

 surface of the abdominal cavity. It gives off twigs to the obturator 

 muscle and then passes through the obturator foramen. After leav- 

 ing the abdominal cavity it gives branches to the accessorius, the 

 obturator, and, the pubio-femoral, or adductor longus muscle. 



The crural plexus gives off another large nerve trunk which ex- 

 tends downward. Shortly after emerging from the plexus it gives 

 off a muscular branch to the ilio-femoralis, or gluteus medius 

 muscle. It then passes between this muscle and the shaft of the 

 femur, to the inner posterior surface of the thigh, and to the inner 

 surface of the knee. It gives off a branch to the structures of the 

 knee. At the knee this nerve terminates in several branches, some 

 of which pass to the inner surface of the tibial head, the internal 

 lateral ligament, the periosteum, the internal condyle, and finally 

 to the upper part of the head of the gastrocnemius muscle. 



The main part of this nerve passes downward as the cutaneous 

 nerve, along the inner surface of the lower thigh. 



The ischiadic plexus (Fig. 64, No. 41) has five to six roots, which 

 fuse into the ischiadic trunk. This main trunk extends out of the 

 abdominal cavity, through the ischiadic foramen, close behind the 

 anterior trochanter of the ilium (Fig. 65, No. i). It gives a branch 

 to the external ilio-femoral or gluteus medius, and a branch to the 

 post-acetabular portion of the ilio-tibialis, or gluteus primus 

 muscle. The main trunk (Fig. 69, No. 13) passes downward to the 

 lower portion of the thigh. In this course there are two branches 

 which run parallel to the femoral artery and the femoral vein. It 

 gives off a small muscular branch to the accessorius, and further 

 down gives off a long slender branch to the outside of the knee- 

 joint. It gives off a lateral cutaneous branch (Fig. 66, No. 7) to 

 the posterior outer portion of the lower thigh. It supplies motor 

 fibers to the external head of the gastrocnemius muscle. 



At the knee region the ischiadica divides into three parts. The 



