POSTERIOR TIBIAL GROUP. 249 



PLANTARIS. 



(Soleus — Peroneo-calcaneus. ) 



(Pl. III. 39.) 



Situated on the postero-external part of the leg, to the out- 

 side of the gastrocnemius, this muscle is, in the horse, slender 

 and rudimentary, with a small, delicate tendon of insertion. 



Origin. — From the external part of the head of the fibula. 



Insertion. — Together with the tendon of the gastrocnemius to 

 the point of the calcaueum. 



Relation. — Externally with the fascia ; internally with the 

 gastrocnemius. 



Action. — It assists very slightly the gastrocnemius. 



FLEXOR PEDIS PERFORATUS.* 



(Femoro-phalangeus.) 



(Fig. 86. b.) 



Situated immediately underneath the gastrocnemius, this muscle 

 is in shape funicular, consisting of a strong fibrous cord, with a 

 slightly fleshy portion above, and arising from the supracondy- 

 loid fossa ; the belly is succeeded by a strong tendon, united to 

 fascia, which is fixed to the inner surface and ridge of the tibia 

 and the summit of the calcaneum, being continuous with the 

 tibial fascia, and enclosing the entire tendo-Achillis. The 

 tendon, at first under that of the gastrocnemius, winds round its 

 inner side, and then surmounts it ; on reaching the point of the 

 calcaneum it forms a cap, giving slips of insertion to the sides of 

 that bone ; a large synovial bursa exists here, which is one of 

 the seats of the lesion termed capped hock. It now descends 

 posteriorly, and is disposed as is the corresponding tendon in the 

 anterior extremity, forming a synovial sheath and ring for the 

 perforans tendon, and finally bifurcating to become attached to 

 the sides of the os coronse. 



Relation. — Posteriorly with the gastrocnemius ; anteriorly with 

 the tibia, the popliteus, perforans, and accessorius muscles. 



* This muscle was formerly described under the name of gastrocnemius in- 

 ternus. The more appropriate one now in use is adopted here. 



