Dorsal interossei of foot

The dorsal interossei of the foot (Latin: musculi interossei dorsales pedis) are four small foot muscles located in the spaces between the metatarsal bones. These four paired muscles stretch between the metatarsal bones and proximal phalanges of the foot. Together with the lumbricals of the foot, flexor digitorum brevis, quadratus plantae and plantar interossei, the dorsal interossei of the foot belong to the central compartment (middle group) of the plantar foot muscles.

Origin

Each dorsal interosseus muscle has two heads, and they originate from the opposing sides of the first to fifth metatarsal bones.

Insertion

The first dorsal interosseus muscle inserts at the medial side of the base of the proximal phalanx of the second toe, while the second through fourth dorsal interossei insert on the lateral sides of the bases of the proximal phalanges of the second, third and fourth toes. Also, they insert at the extensor expansions of the second to fourth fingers of the foot.

Action

The dorsal interossei muscles of the foot abduct and flex the toes at the second to fourth metatarsophalangeal joints. Also, these muscles provide toe extension at the second to fourth interphalangeal joints.

Innervation

The dorsal interossei are innervated by the lateral plantar nerve (S2 - S3) - a terminal branch of the tibial nerve.

Blood supply

The dorsal interossei muscles of the foot receive arterial blood supply from the branches of the anterior tibial artery via the dorsalis pedis and dorsal metatarsal arteries and from the posterior tibial artery via the lateral plantar and plantar metatarsal arteries.