Lateral malleolus

The lower extremity (distal extremity; external malleolus) of the fibula is of a pyramidal form, and somewhat flattened from side to side; it descends to a lower level than the medial malleolus.

The lateral surface is convex, subcutaneous, and continuous with the triangular, subcutaneous surface on the lateral side of the body.

The medial surface presents in front a smooth triangular surface, convex from above downward, which articulates with a corresponding surface on the lateral side of the talus. Behind and beneath the articular surface is a rough depression, which gives attachment to the posterior talofibular ligament.

The anterior border is thick and rough, and marked below by a depression for the attachment of the anterior talofibular ligament.

The posterior border is broad and presents the shallow malleolar sulcus, for the passage of the tendons of the Peronæi longus and brevis.

The summit is rounded, and gives attachment to the calcaneofibular ligament.

Often when a patient fractures their ankle, this is the bone that suffers a chip or other significant damage.