Second metatarsophalangeal joint

The second metatarsophalangeal joint (MTPJ) is a synovial condyloid joint formed by the articulation of the head of the second metatarsal and the base of the proximal phalanx of the second toe. The joint is stabilized by several key structures:

• Plantar plate: A thick fibrocartilaginous structure on the plantar aspect, firmly anchored proximally to the metatarsal head by a stout fibrous pedicle and distally to the base of the proximal phalanx. It merges with the collateral ligaments and the deep transverse intermetatarsal ligament, and is the primary stabilizer against dorsal subluxation and hyperextension. The plantar plate also serves as the main distal insertion of the plantar fascia and is closely associated with the flexor tendons.

• Collateral ligaments: Medial and lateral collateral ligaments reinforce the joint capsule and attach from the metatarsal head to the base of the proximal phalanx, providing mediolateral stability.

• Joint capsule: A fibrous capsule encloses the joint, blending with the plantar plate and collateral ligaments. The dorsal capsule is thinner, while the plantar aspect is reinforced by the plantar plate.

• Deep transverse metatarsal ligament: Connects adjacent metatarsal heads and merges with the plantar plate, contributing to transverse stability.

• Tendons: The flexor digitorum longus and brevis tendons pass plantar to the joint, while the extensor digitorum longus and brevis tendons cross dorsally.

The vascular supply to the plantar plate is derived from both the metatarsal pedicle and the plantar fascia, with the majority entering proximally from the metatarsal side.