Anatomy of the plantar plate and its attachments in the lesser metatarsal phalangeal joint.

The plantar plate is a rarely seen, yet central structure to the lesser metatarsal phalangeal (MP) joint. Thirty cadaver lesser MP joints were studied to obtain a detailed description of the plate, including its dimensions, connections, and histology. The plate was found to be made of fibrocartilage with fiber orientation which suggests that it withstands tensile loads in line with the plantar fascia as well as the compressive loads from the metatarsal head. The plantar plate was the most substantial distal insertion of the plantar fascia. Impressive plantar plate attachments were noted to the proximal phalanx, the major longitudinal bands of the plantar fascia, and the collateral ligaments. The plate and collateral ligaments formed a substantial soft tissue box connected to the sides of the metatarsal head. From the dissections, it is apparent that malposition of the toe at the MP joint is likely over time to be associated with pathology in both the collateral ligaments and the plate. Because of these attachments and a close association with the flexor tendons to the lesser toe, the plate can be compared with the sesamoid mechanism of the first MP joint.