To fully understand the research literature on the efficacy of various clinical procedures, the physical therapist must be knowledgeable in the anatomy and biomechanics of the synovial joints. This paper presents detailed information on the bony, ligamentous, muscular, and vascular anatomy of the subtalar joint. In addition, there is a discussion of the joint axis as well as the joint motions about this axis. This information will prove valuable to the clinician as new examination and treatment procedures are considered for inclusion in the management of patients with foot-ankle dysfunction.