Subtalar Joint
Also written as: STJ — Subtalar Joint
The articulation between the talus and calcaneus that controls triplanar rearfoot motion, including inversion, eversion, and rotation, and is a primary target of rearfoot orthotic control.
Full Definition
The subtalar joint (STJ) is a complex triplanar joint formed between the posterior facet of the talus superiorly and the posterior calcaneal facet inferiorly. Its primary motion is triplanar: pronation (eversion, abduction, dorsiflexion) and supination (inversion, adduction, plantarflexion). The STJ transmits rotational forces between the lower limb and foot, making it a key lever point for orthotic rearfoot control. Rearfoot posts, heel cups, and medial arch supports are all designed to influence STJ kinematics. Note that 'subtalar joint neutral' (a separate listed concept) describes a specific positional reference point distinct from the joint itself.
Usage
Usage note: STJ is acceptable after first use. Editors should note that 'subtalar' is one word (not 'sub-talar') per standard anatomical convention.
In Context
- "Excessive subtalar joint pronation during midstance was identified as the primary driver of medial knee pain in this patient." — Biomechanical assessment report
- "The rearfoot post was designed to limit subtalar joint eversion to within 2° of neutral throughout the stance phase." — Orthotic prescription letter