Talus

Study entry

Parts

A tarsal bone formed by a body, neck and head. On top, the trochlea articulates with the two malleoli and receives the weight that comes from the tibia; behind, the posterior process has a groove for the tendon of the flexor hallucis longus. It is the only tarsal bone without attachment of a muscle or tendon, and almost its whole surface is cartilage.

Joints

Talocrural (trochlea with the tibia and fibula); with the calcaneus, below; with the navicular, through the head (supported by the plantar calcaneonavicular ligament).

Palpation

The head, between the sustentaculum tali and the tuberosity of the navicular (more prominent with the foot everted); with the foot in plantar flexion, the upper surface of the body, in front of the ankle.

Source: cap. 7, «Huesos del miembro inferior: huesos del pie: tarso»

Clinical correlation

Fracture of the neck of the talus

It happens in violent dorsiflexion of the ankle, as when stamping on the brake with full force in a head-on collision. Sometimes the body of the talus is displaced backward.

Os trigonum

The secondary center that forms the lateral tubercle of the talus sometimes does not unite with the body of the bone, perhaps because of forced plantar flexion in adolescence; or the already ossified center breaks and does not heal. An accessory ossicle remains, the os trigonum, present in 14% to 25% of adults, almost always in both feet and more common in soccer players and dancers.

Related clinical cases

• Fracture of the neck of the talus
• Os trigonum

Other structures in this region

• Hip bone
• Femur
• Patella
• Tibia
• Fibula
• Calcaneus
• Navicular
• Cuboid