The plantar interossei are a group of intrinsic muscles within the foot. They form the deepest layer of plantar muscles and have a unipennate shape. Attachments: Originates from the medial side of metatarsals three to five. Attaches to the medial sides of the phalanges of digits three to five. Actions: Adduction of the lateral three digits and flexion at the metatarsophalangeal joints. Innervation: Lateral plantar nerve. Blood Supply: Lateral plantar artery By TeachMeSeries Ltd (2025) Fig 5The fourth layer of the plantar muscles. Note the unipennate shape of the plantar interossei, and the bipennate shape of the dorsal interossei Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Print Article Rate This Article