THE LIMBS OF THE HORSE 129 



intimately related to that of the plantaris muscle. At first the plan- 

 taris tendon is the deeper of the two ; but, twisting spirally round the 

 medial edge of the tendon of the gastrocnemius, it becomes the more 

 superficial before the summit of the tuber of the calcaneus is reached. 

 An extensive synovial bursa intervenes between the two tendons from 

 the point where the twist begins to about the middle of the tarsus. A 

 strong but narrow fascial band springs from the femur close to the 

 origin of the lateral head of the gastrocnemius, and, running down the 

 surface of this muscle, is blended with its tendon, as well as that of the 

 plantaris. 



The insertion of the gastrocnemius is to a transversely disposed 

 depression on the summit of the tuber of the calcaneus, a small 

 synovial bursa intervening between the tendon and the anterior convex 

 area of the tuber. 



M. SOLEUS. — The narrow, thin soleus ^ muscle lies along the lateral 

 border of the gastrocnemius. Its origin is from the head of the fibula, 

 and its slender tendon joins that of the gastrocnemius. 



Dissection. — Cut across the gastrocnemius muscle just where the two 

 heads are about to join. The reflexion of the lateral head is made a 

 little difficult by its close connection with the underlying plantaris 

 muscle. 



M. PLANTARIS.^ — The rounded plantaris ^ muscle possesses a strength 

 out of all proportion to its volume, from the circumstance that it is 

 mainly composed of tendinous tissue among which are scattered 

 muscular fibres. The origin of the muscle is from the depths of the 

 plantaris fossa, where it is closely connected with the lateral head of 

 the gastrocnemius. As has been already noted, its powerful, rounded 

 tendon curves spirally round that of the gastrocnemius, and flattens out 

 over the summit of the tuber of the calcaneus, to which it is attached 

 by a medial and a lateral slip. As previously stated, a large synovial 

 bursa is interposed between the plantaris and gastrocnemius tendons 

 and between the plantaris tendon and the bone. 



From the tuber of the calcaneus, the plantaris tendon appears to be 

 continued into the metatarsus ; but there is reason for regarding this 

 apparent continuation as a modified short flexor of the digit (m. flexor 

 digitorum brevis). 



1 Solea [L.], a sole fish (in a borrowed sense, from the outline of the fish having a 

 resemblance to the sole of the human foot). The name is given to the human 

 muscle on account of its shape. 



2 This muscle is often termed the superficial flexor of the digit— ra. flexor digi- 

 torum (pedis) sublimis. 



3 Plantaris [L.] (from planta, the sole of the foot), of or belonging to the sole of 



the foot. Digitized by Microsoft® „ 



