The deep band of the plantar aponeurosis of the human foot.

The deep band of the plantar aponeurosis is a variable structure formed by fibers from both the medial and lateral portions of the plantar aponeurosis. This band courses directly to the plantar ligament of the fourth metatarsophalangeal joint. Proximally it is superficial. Distally it passes deep to the tendons of the flexor digitorum longus to attach at the metatarsophalangeal joint. The second plantar and third and fourth dorsal interosseous muscles as well as the transverse head of adductor hallucis have attachments to the deep aponeurotic band. This band becomes taut when the proximal phalanx of the fourth toe is extended. No recent references to this structure could be found. The function of the deep band of the plantar aponeurosis is unknown, although the anatomical arrangement may make it important in stabilizing the fourth ray of the foot during locomotion.