Fibula The fibula is the lateral bone of the leg skeleton. It is a slender, splint-like bone that is slightly expanded at both ends. It plays no role in the weight-bearing function of the lower limb, but

serves as a signifi cant site of muscle attachment. It is not easily palpable except at its proximal and distal ends, the shaft being totally surrounded with muscle. The fi bula articulates with two bones — the tibia and talus.

10Articular facet for talus

11Malleolar fossa

12Malleolar groove

5

5

6 7

9

12

112

2

3

113

Like the hand, the foot is a composite structure comprised of 26 bones, not counting the small sesamoid bones that are found in certain tendons. The proximal end of the foot is the tarsus or ankle. There are seven tarsal bones

that show a greater range in size and shape than their carpal counterparts in the hand. Distal to the tarsals are the fi ve digital rays. The four lateral digits consist of a metatarsal bone and three phalanges. The large medial digit, the hallux or great toe, has a metatarsal bone and only two phalanges. Two prominent sesamoid bones (bones that form in tendons) are present on the plantar surface at the head end of the first metatarsal.

114

115

The calcaneus is the largest bone of the foot and its long axis parallels the long axis of the foot.

Its distal end forms a series of articular surfaces with neighboring bones. Its posterior or proximal end is box-like and forms a roughened calcaneal tubercle at the posterior surface. The calcaneus articulates with two bones — the talus and the cuboid.

117