The leg having to support the weight of the body has its bones strongly made. The tibia bears nearly all the weight because it articulates with the femur above and astragalus below and transmits the pressure directly from one to the other. The fibula is slight compared to the tibia and lies posterior to it and to the outer side.

The leg bones receive the insertion of the thigh muscles above and give attachment to the muscles which move the foot. The leg therefore is capable of being influenced by the movements of the foot below and the thigh above. 35

Surface Anatomy

At the upper end of the leg can be felt the two tuberosities of the tibia. The lower edge of the tuberosities is on a line with the upper edge of the tubercle. The head of the fibula is almost level with (a little above) the tubercle of the tibia and is situated far posteriorly. Attached to the head of the fibula above is the biceps tendon accompanied by the external popliteal (fibular) nerve and the long external lateral ligament. The tendo patellae is attached to the tibial tubercle. The tibia is triangular in shape with a sharp edge - the crest or shin - forward, thus forming two surfaces, an internal and an external. The posterior surface is covered by muscles and is inaccessible. The internal surface is subcutaneous and leads down to the internal malleolus. The external surface has the extensor muscles between it and the fibula. The fibula a short distance below its head becomes covered by the peronei muscles and only becomes subcutaneous in its lower anterior fourth. The upper portion of the leg is largely muscular, but at its lower portion it is mainly tendinous. By placing a finger over the muscles while the foot is moved one is enabled to determine whether or not they are paralyzed (Fig. 558).

Fig. 558.   Surface anatomy of the leg.

Fig. 558. - Surface anatomy of the leg.