Talus

Function

The keystone dropped into the ankle mortise — it has no muscle attachments at all. It converts tibial force into foot motion, steering the subtalar joint's inversion-eversion dance.

Landmarks

• Head
• Neck
• Body
• Trochlea
• Lateral and medial processes
• Sulcus tali

Articulations (joints)

• Tibia and fibula (ankle mortise)
• Navicular (talonavicular joint)
• Calcaneus (subtalar joint)

Clinical relevance

The talus' retrograde blood supply via the tarsal sinus makes its neck fractures prone to avascular necrosis (a Hawkins sign — subchondral lucency at 6–8 weeks — signals preserved blood supply; its absence raises concern). Talar dome osteochondral lesions linger after 'sprains'.