Flexor Hallucis Longus Tendon Groove On The Calcaneus, Inferior View

Description

Calcaneus anatomy is centered on the plantar (inferior) surface of the heel bone, with the groove for the flexor hallucis longus (FHL) tendon coursing obliquely beneath the sustentaculum tali on the medial side. From this inferior perspective, the sulcus lies posterior to the anterior calcaneal articular region and inferior to the middle facet for the talus, forming a defined channel that directs the FHL as it transitions toward the plantar foot. Medially, the shelf-like sustentaculum tali overhangs the groove, while the lateral calcaneal surface and the broader plantar tuberosity sit farther lateral and posterior. Sharp bony relief is emphasized. That topography matters because the FHL tendon can become irritated where it is constrained by bone and fibro-osseous boundaries, a common pain generator in dancers and runners with FHL stenosing tenosynovitis and triggering of the hallux. The sulcus also provides a stable landmark when teaching hindfoot anatomy alongside the nearby tarsal tunnel contents, since the tendon’s course under the sustentaculum tali helps distinguish it from the flexor digitorum longus and tibialis posterior tendons as they approach the plantar foot. Bony grooves are unforgiving. This fixed inferior view keeps attention on the calcaneal morphology that shapes tendon tracking, which is useful when correlating symptoms to sites of mechanical impingement or when reviewing hindfoot endoscopic approaches that navigate adjacent to the subtalar joint. Use this illustration in gross anatomy or podiatric medicine courses when covering the calcaneus, subtalar joint region, and plantar soft-tissue pathways, and in orthopedic or sports medicine publications discussing FHL tendinopathy, hindfoot arthroscopy landmarks, or calcaneal fracture patterns that can alter the tendon groove. It also fits radiology teaching files as a reference for CT or MRI correlation of the sustentaculum tali region and FHL tendon course. Anatomical accuracy verified by SciePro's Medical Advisory Board.