Talus bone


 * See talus for other meanings of the word

The talus bone or astragalus of the ankle joint connects the leg to the foot.

The talus is the second largest of the tarsal bones.

It articulates with the tibia, fibula, calcaneus, and navicular.

It occupies the middle and upper part of the tarsus, supporting the tibia above, resting upon the calcaneus below, articulating on either side with the lateral and medial malleoli, and in front with the navicular.

The neck (collum tali)
The neck is directed forward and medialward, and comprises the constricted portion of the bone he oval head.

Its upper and medial surfaces are rough, for the attachment of ligaments; its lateral surface is concave and is talocalcaneal ligament]].

The head (caput tali)
The head looks forward and medialward; its anterior articular or navicular surface is large, oval, and convex.

Its inferior surface has two facets, which are best seen in the fresh condition.

The medial, situated in front of the middle calcaneal facet, is convex, triangular, or semi-oval in shape, and rests on the plantar calcaneonavicular ligament; the lateral, named the anterior calcaneal articular surface, is somewhat flattened, and articulates with the facet on the upper surface of the anterior part of the calcaneus.

Use as dice
Due to the way that the talus bone is shaped, it can land in one of four positions. This fact led to the bone assuming a role as a form of die in games of chance and gambling, such as Knucklebones.