456 MUSCLES. 



A tendinous facing exists externally also in this muscle, to 

 which its fibres proceed obliquely. This tendon is continued 

 through the fossa at the back part of the malleolus externus, be- 

 ng covered by the tendon of the peroneus longus, and confined 

 by the same ligamentous noose; passing through the superficial 

 fossa at the outer side of the os calcis, it is inserted into the ex- 

 ternal part of the base of the metatarsal bone of the little toe. 



Jt extends the foot, and presents the sole obliquely down- 

 wards. It corresponds with the flexor carpi ulnaris.* 



Triceps Surce. 



The muscular mass on the back of the leg, constituting its 

 calf, is formed by the two following muscles, which, with much 

 reason, may be considered as composing only one. Anatomists, 

 who view them in this latter light, describe them under the 

 name of Triceps Sura?, of which the Gastrocnemius portion has 

 two heads, and the Soleus, or Gastrocnemius internus, but one. 



1. The Gastrocnemius is the most superficial muscle on the 

 back of the leg, and conceals the other, in consequence of its 

 breadth. It comes from the condyles of the os femoris by two 

 heads. One head arises, tendinous, from the up-per back part of 

 the internal condyle, and fleshy from the ridge leading to the 

 linea aspera: the other head arises, by a broad tendon in the 

 same way, from the external condyle and the ridge above it. 

 A triangular vacancy is left between the heads of the muscle 

 for the passage of the popliteal vessels; the heads then join to- 

 gether, but in such a way that the appearance of two bellies is 

 distinctly preserved, of which the internal is the largest. The 

 muscular fibres pass from a broad tendinous facing on the back 

 to a corresponding one on the front surface of the muscle, from 

 the latter of which comes the tendo-achillis. 



2. The Soleus is beneath the Gastrocnemius, and arises, fleshy, 

 from the posterior part of the head of the fibula, and from the 

 external angle of that bone, for two-thirds of its length down, 

 behind the peroneus longus. It also arises, fleshy, from the ob- 



* Varieties. It is sometimes double. 



