n8 



ANATOMY AND PHYSIOLOGY 



CALF MUSCLES (FIGS. 93, 97) 



Triceps surse, and plantaris. 



The gastrjgcjififliius. Origin. Bv two hea^s iust above the 



i i "5^'^^r . i r 



condyles of the femur. 



Insertion. On the calcaneus. 



Note. The two heads form the 

 lower boundaries of the popliteal 

 space. 



The soleus is covered by the gas- 

 trocnemius. ^Origin. Medial border 

 of the tibia and lateral border of the 

 fibula. Insertion. The os calcis, 

 with trie above muscle. 



Action of the two. They join to 

 form one muscle, the triceps surae (or 

 triceps of the calf), which has the 

 strongest tendon in the body, the tendo 

 calcaneus (tendon of Achille^) by 

 which they are attached to the os 

 calcis, and, therefore, they lift the he'e^ 

 If the muscles of both legs act at the 

 same time, the whole body is lifted on 

 the toes. 



Nerve to both. Tibial. 



The plantaris. Origin. With the outer 

 head of the gastrocnemius. Insertion. 

 With the tendo calcaneus. 



Note. The belly is short and small; the 



, 9 -itie 



FIG. 97. LATERAL ASPECT AND 

 CALF or LEG. 



i, 2, 3, 4, Lateral view, mus- 

 cles passing in front of ankle; 5, 

 6, peroneus brevis and p. lon- 

 gus (behind ankle) ;* 7, 8, soleus tendon is the longest in the body, 

 and gastrocnemius; 9, hea3~Df 



fibula! 10, biceps femoris; n, The calf muscles constitute a group 



Ach^ms^^armula/li a.men f & reat P ower > as b Y them one lifts 

 16, 17, insertions of peroneus oneself to stand upon the toes, 

 tertius and brevis; 18, short ex- ,_. . A 1 ^ - 



tensor of toes; 19, plantar mus- The sole of the foot, or plantar 

 cle; 20, patella. (Sappe)?.) region, resembles the palm of the 



hand in having special groups of mus- 

 cles for the great and little toes, with the long flexor tendons 

 lying between them, and a dense fascia covering them. This is 

 called the plantar fascia. 



The nerves are medial and lateral plantar. 



