The sustentaculum tali has what attached to it as a shelf?

• A. Tibialis posterior
• B. Extensor hallucis longus
• C. Flexor hallucis longus (shelf)
• D. Peroneus longus

Answer: (C)

The sustentaculum tali provides a shelf-like path for the tendon of the flexor hallucis longus. After the tendon courses behind the medial malleolus, it travels under the sustentaculum tali, where an inferior groove on the calcaneus holds and guides the tendon as it moves to the plantar aspect to flex the big toe. This shelf-like groove stabilizes the tendon and prevents bowstringing. The other tendons listed don’t pass under this part of the calcaneus in a way that forms such a shelf.