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, middle, 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
