Flexor Digiti Minimi Brevis, Plantar View

Description

Arising from the plantar aspect of the cuboid and the adjacent tendon sheath of the fibularis (peroneus) longus, the flexor digiti minimi brevis runs distally along the lateral sole to the fifth toe. Its muscle belly lies superficial to the plantar interossei and lateral to the flexor digitorum brevis, then continues as a tendon on the plantar surface of the fifth metatarsophalangeal joint. The tendon inserts on the lateral side of the base of the proximal phalanx of digit V, traveling medial to the abductor digiti minimi as both approach the little toe. Small sesamoid elements and the plantar plate at the MTP joint may be implied at the level of the tendon’s terminal course. Plantar isolation of this muscle matters because it clarifies the functional division between abduction and flexion of the fifth digit and helps explain lateral forefoot pain patterns that are otherwise attributed only to bony deformity. Increased load across the fifth ray, as seen with tailor’s bunion (bunionette) and associated MTP capsulitis, can irritate the plantar soft tissues where the flexor digiti minimi brevis tendon blends with the plantar plate. Surgical planning around bunionette correction and fifth MTP procedures benefits from a clear map of this lateral compartment, including the relationship to the fibularis longus tendon groove and the plantar neurovascular branches that course nearby. Small muscle, common source of confusion. Use this asset for anatomy and podiatry teaching on the intrinsic muscles of the sole, for operative atlases covering fifth ray disorders, or as a figure in sports medicine texts discussing lateral forefoot overuse and MTP instability. Anatomical accuracy verified by SciePro's Medical Advisory Board.