THE LOWER EXTREMITIES. 195 



of the leg. Its head is small and placed toward the 

 back of the tibia below the knee-joint, from which it is 

 excluded. The head articulates with the external 

 tuberosity and has extending upward from it the styloid 

 process. To it is attached the biceps tendon or outer 

 hamstring. At the lower extremity of the shaft is the 

 external malleolus, which articulates with the astragalus 

 and forms the outer ankle. The only parts of the fibula 

 that can be felt, besides the malleolus, which is very 

 prominent, are the head and the lower external surface 

 of the shaft. 



In fracture of the leg both bones are usually broken, 

 though either may be broken separately. Pott's fracture 

 is fracture of the lower fibula, and may be caused by 

 stamping hard when stepping on to the sidewalk. In 

 rickets the tibia becomes bowed outward and forward, 

 causing bow leg, a condition which in very young children 

 may be rectified by manipulation. Later on braces are 

 needed and after five years the bones have to be broken 

 and set straight. 



The Ankle. The ankle or tarsus has but seven bones 

 where the wrist has eight. They are the os calcis or 

 heel bone, which is the largest and strongest and forms 

 the tuberosity of the heel; the astragalus, which is next 

 largest and helps to form the ankle-joint; the cuboid; the 

 navicular (boat-like) or scaphoid; and the internal, mid- 

 dle, and external cuneiform bones. The astragalus is 

 above and partially in front of the os calcis, to which is 

 attached the tendo Achillis. The cuboid is on the outer 

 side of the foot, in front of the os calcis and behind the 

 metatarsals. It is noticeable in congenital club-foot, in 

 which condition the tarsal bones may be distorted in 

 shape and misplaced. The navicular or scaphoid is on 

 the inner side of the foot, between the astragalus and 

 the three cuneiform bones. 



The Foot. There are five metatarsal bones in the foot, 

 corresponding to the five metacarpals in the hand, and 

 the toes have the same number of phalanges as the 



