Dorsal interossei of the foot

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Dorsal interossei of the foot are muscles located in the foot, specifically between the metatarsal bones. They play a crucial role in the movement and stability of the foot. There are four dorsal interossei muscles in the human foot, and they are part of the intrinsic muscles of the foot that originate and insert within the foot itself.

Anatomy

The dorsal interossei muscles of the foot are bipennate, meaning they have a central tendon with muscle fibers extending diagonally from either side. They originate from the adjacent sides of the metatarsal bones and insert into the bases of the proximal phalanges and the extensor expansion of the toes. Unlike their counterparts in the hand, the dorsal interossei of the foot are numbered from one to four, starting from the medial side (the side closest to the body's midline).

Function

The primary function of the dorsal interossei muscles is to abduct the toes, which means they move the toes away from the second toe, which is considered the line of the foot's axis. Additionally, they assist in flexion of the metatarsophalangeal joints (the joints where the toes connect to the foot) and extend the interphalangeal joints (the joints between the phalanges of the toes). This action is essential for the proper distribution of body weight across the foot during walking and for the push-off phase during running.

Innervation

The dorsal interossei muscles of the foot are innervated by the lateral plantar nerve, a branch of the tibial nerve. This nerve supplies the muscles with the necessary signals from the brain to contract and perform their functions.

Clinical Significance

Dysfunction or injury to the dorsal interossei muscles can lead to difficulties in walking and maintaining balance. Conditions such as metatarsalgia, a type of foot pain concentrated at the front near the metatarsals, can arise from issues with these muscles. Additionally, abnormalities in the function or structure of the dorsal interossei can contribute to deformities such as hammer toe or claw toe.

See Also

• Intrinsic muscles of the foot
• Metatarsal bones
• Metatarsophalangeal joints
• Interphalangeal joints