The dorsal interossei are a group of intrinsic muscles within the foot. They form the deepest layer of plantar muscles and have a bipennate shape.
- Attachments: Originates from the lateral aspect of the metatarsals. The first muscle attaches to the medial side of the proximal phalanx of the second digit. The second to fourth interossei attach to the lateral sides of the proximal phalanxes of digits two to four.
- Actions: Abduction of the lateral four digits and flexion at the metatarsophalangeal joints.
- Innervation: Lateral plantar nerve.
- Blood Supply: Dorsalis pedis, dorsal metatarsal, lateral plantar and plantar metatarsal arteries.