Il8 ANATOMY OF THE DOMESTIC FOWL 



Origin. — There are three heads: the internal, the external, and 

 the tibial. The external head extends by a short, flattened, strong 

 tendon from the postero-external part of the external condyle of 

 the femur; the internal head extends from the outer surface of the 

 inner condyle of the femur; and the tibial head extends from the 

 entire iimer rim of the tibial summit and from the free edge of the 

 adjacent crest. 



Insertion. — ^At the lower fourth of the tibial shaft, terminates in 

 a broad, flat tendon which passes over the shallow, longitudinal 

 groove of the tibial cartilage, and, crossing the tibio-tarsal joint, 

 is inserted to the posterior surface of the hypotarsus of the metatarsal 

 bone, and finally, below this point, merges into the podothecal 

 -sheath confining the flexor tendons. 



Shape. — Large, fleshy, somewhat cone-shaped with the base 

 upward. 



Relations. — The posterior fleshy muscle of the post^tibial region 

 located anterior to the soleus. 



Action. — ^Extends the metatarsus on the tibia. 



Soleus (Fig. 25, No. G, i). Location. — The posterior tibial region. 



Origin. — From the posterior part of the head of the tibia. 



Insertion. — By a long slender tendon to the proximal end and 

 toward the inner angle of the tibial cartilage, some of the fibers 

 passing to the tendon of the gastrocnemius. 



Shape. — Small, flattened. 



Relations. — Anteriorly, with the flexor perforans digitorum pro- 

 fundus and posteriorly, with the gastrocnemius. 



Action. — Similar to that of the gastrocnemius. 



Peroneus Longus (Fig. 23, Nol 12). Location. — Antero-lateral 

 tibial region. 



Origin. — From the raised crest in front of the head of the tibia, 

 and from the fascia that covers the outer side of the knee-joint. 



Insertion.-^The fibers, passing downward, then downwa!rd and 

 outward, terminate in a small tendon- at the lower third of the tibia. 

 This tendon bifurcates just above the tibial condyles at the outer 

 part of the Umb, the shorter and stronger attaches to the fibrous 

 fascia covering the tibial cartilage, the other merging 'with the 

 tendon of the flexor perforatus medius primus pedis about i cen- 

 timeter below the hypotarsus of the tarso-metatarsus. 



Relations. — Covers over all the muscles of the anterior tibial 

 region. 



