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