546 THE MUSCLES AND FASCIA 



of the Peroneus longus. On the dorsum of the foot the tendons of .the Extensor muscles, 

 emerging from beneath the anterior annular ligament, spread out and can be distinguished 

 in the following order: The most internal and largest is the Tibialis anticus, then the Extensor 

 proprius hallucis; next comes the Extensor longus digitorum, dividing into four tendons to 

 the four outer toes; and lastly, most externally, is the Peroneus tertius. The flattened form of 

 the dorsum of the foot is relieved by the rounded outline of the fleshy belly of the Extensor 

 brevis digitorum, which forms a soft fulness on the outer side of the tarsus in front of the external 

 malleolus, and by the Dorsal interossei, which bulge between the metatarsal bones. At the 

 back of the knee is the popliteal space, bounded above by the tendons of the Hamstring muscle; 

 below, by the two heads of the Gastrocnemius. Below this space is the prominent fleshy mass 

 of the calf of the leg, produced by the Gastrocnemius and Soleus. When these muscles are 

 in action, as in standing on tiptoe, the borders of the Gastrocnemius are well defined, presenting 

 two. curved lines, which converge to the tendon of insertion. Of these borders, the inner is 

 more prominent than the outer. The fleshy mass of the calf terminates somewhat abruptly 

 below in the tendo Achillis, which stands out prominently on the lower part of the back of the 

 leg. It presents a somewhat tapering form in the upper three-fourths of its extent, but widens 

 out slightly below. When the muscles of the calf are in action, the lateral portions of the Soleus 

 may be seen, fofniing curved eminences, of which the outer is the longer, on either side of the 

 Gastrocnemius. Behind the inner border of the lower part of the shaft of the tibia a well- 

 marked ridge, produced by the tendon of the Tibialis posticus, is visible when this muscle is in 

 a state of contraction. On the sole of the foot the superficial layer of muscles influences surface 

 form; the Abductor minimi digiti most markedly. This muscle forms a narrow 7 rounded 

 elevation along the outer border of the foot, while the Abductor hallucis does the same, though 

 to a less extent, on the inner side. The Flexor brevis digitorum, bound down by the plantar 

 fascia, is not very apparent; it produces a flattened form, covered by the thickened skin of the 

 sole, which is here thrown into numerous wrinkles. 



APPLIED ANATOMY OF THE LOWER EXTREMITY. 



The student should now consider the effects produced by the action of the various muscles 

 in fractures of the bones of the lower extremity. The more common forms of fractures are 

 selected for illustration and description. . 



PYRIFORMIS. 



EMELLUS SUPERIOR. 

 OBTURATOR INTERNUS. 

 GEMELLUS INFERIOR. 



BTURATOR EXTERNUS. 

 QUADRATUS FEMORIS. 



FIG. 403. Fracture of the neck of the femur within the capsular ligament. 



In fracture of the neck of the femur internal to the capsular ligament (Fig. 403) the charac- 

 teristic marks are slight shortening of the limb and eversion of the foot, neither of which symp- 

 toms occurs, however, in certain cases until some time after the injury. The eversion is caused 



