THE ANATOMY OF THE ELK. 



385 



Muscles of the Leg : Posterior Tibial Begion. 



Gastrocnemius arises by two heads, one from the outer, and the other 

 from the inner condyloid ridge of the femur. The heads unite together 

 about the lower third of the tibia, and are inserted by means of a stout 

 tendon which splits into two parts, a superficial and a deep. The superficial 

 extends as far as the lower end of the metatarsal bone, where it divides 

 into two slips which are inserted into the bases of the second phalanges of 

 the anterior toes. Between these slips the tendon of the flexor perforans 

 passes forward to the toes. The deeper portion of the tendon is inserted 

 into the tuberosity of the os calcis. 



This description includes under one head both the flexor perforatus and 

 gastrocnemius, these two muscles being inseparably united. With refe- 

 rence to the muscles of this region we have departed slightly from the 

 nomenclature of Chauveau, our plantaris forming a portion of his flexor 

 perforatus. 



Soleus is fusiform and arises along with the outer head of the gastro- 

 cnemius. It terminates by joining the tendon of this latter muscle. 



Plantaris is a delicate muscle which arises from the external condyloid 

 ridge of the femur, and from the posterior part of the capsule of the knee- 

 joint. It terminates by blending with the outer head of the gastrocnemius. 



Popliteus arises by a strong tendon from a pit on the outer side of the 

 external condyle of the femur. Its fleshy belly is inserted into the upper 

 third of the posterior surface of the tibia. 



Flexor perforans digitorum. — Arises by three heads. The superficial 

 head is attached to the posterior border of the external tuberosity of the 

 tibia. The two deeper heads arise, one from the posterior surface of the 

 upper two thirds of the tibia with the exception of so much of the bone as 

 aff'ords insertion to the popliteus, and from an intermuscular septum at- 

 tached to the external border of that bone ; whilst the other springs from 

 the internal and lower half of the oblique line of the tibia, and separates 

 the second head of origin of this muscle from the popliteus. The tendons 

 derived from the first and second heads unite opposite the lower end of the 

 tibia and are joined below the ankle-joint by that of the third head. The 

 common tendon thus formed passes as far as the lower end of the meta- 

 tarsal bone, where it divides into two slips, one of which is inserted into 

 the base of the last phalanx of each of the anterior toes, after passing be- 

 tween the tendinous slips supplied to the same toes by that part of the gas- 

 trocnemius which corresponds to the flexor perforatus. The third head of 

 origin of the flexor perforans corresponds to the oblique flexor of the pha- 

 langes of Chauveau. 



Interossei. — These are represented almost entirely by ligament corre- 

 sponding to the suspensory ligament of the fetlock in the horse. It con- 

 sists of a stout musculo-tendinous band, which extends along the whole 

 length of the metatarsus. The muscular portion does not appear to be 

 arranged in any definite manner. Above the metatarso-phalangeal articu- 



