In human anatomy, the dorsal interossei of the foot are four muscles situated between the

metatarsal The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the me ...

bones.

Origin

The four interossei muscles are bipenniform muscles each originating by two heads from the proximal half of the sides of adjacent metatarsal bones.

Insertion

The two heads of each muscle form a central tendon which passes forwards deep to the deep

transverse metatarsal ligament The transverse metatarsal ligament is a narrow band which runs across and connects together the heads of all the metatarsal bones. It is blended anteriorly with the plantar (glenoid) ligaments of the metatarsophalangeal articulations. Its plantar ...

. The tendons are inserted on the bases of the second, third, and fourth

proximal phalanges The phalanges (singular: ''phalanx'' ) are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones. ...

and into the

aponeurosis An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

of the tendons of the

extensor digitorum longus The extensor digitorum longus is a pennate muscle, situated at the lateral part of the front of the leg. Origin and insertion It arises from the lateral condyle of the tibia; from the upper three-quarters of the anterior surface of the body of t ...

Gray's Anatomy, 1918 (see infobox) without attaching to the extensor hoods of the toes. Thus, the first is inserted into the medial side of the second toe; the other three are inserted into the lateral sides of the second, third, and fourth toes.

Action

The dorsal interossei abduct at the

metatarsophalangeal joints The metatarsophalangeal joints (MTP joints), also informally known as toe knuckles, are the joints between the metatarsal bones of the foot and the proximal bones (proximal phalanges) of the toes. They are condyloid joints, meaning that an ellipti ...

of the third and fourth toes. Because there is a pair of dorsal interossei muscles attached on both sides of the second toe, simultaneous contraction of these muscles results in no movement. This arrangement of dorsal interossei makes the second toe the midline of the foot, whereas the midline of the hand (marked by dorsal interossei of hand) is in the third finger. Abduction is of little importance in the foot, but, together with the plantar interossei, the dorsal interossei also produce flexion at the metatarsophalangeal joints. Although small, the dorsal interossei are powerful muscles that, together with their plantar counterparts, control the direction of the toes during violent activity, thus allowing the long and short flexors to perform their actions. Because of the relationship to the metatarsophalangeal joints, the interossei muscles also contribute to maintaining the anterior metatarsal arch of the foot and also, to a limited extent, the medial and lateral longitudinal arches of the foot.

Innervation

All dorsal interossei are innervated by the

lateral plantar nerve The lateral plantar nerve (external plantar nerve) is a branch of the tibial nerve, in turn a branch of the sciatic nerve and supplies the skin of the fifth toe and lateral half of the fourth, as well as most of the deep muscles, its distribution ...

(S2–3). Those in the fourth interosseous space are innervated by the superficial branch and the other by the deep branch. The first and second dorsal interossei muscles additionally receive innervation from the lateral branch of the

deep fibular nerve The deep fibular nerve (also known as deep peroneal nerve) begins at the bifurcation of the common fibular nerve between the fibula and upper part of the fibularis longus, passes infero-medially, deep to the extensor digitorum longus, to the anteri ...

Relations

In the angular interval left between the heads of each of the three lateral muscles, one of the perforating arteries passes to the dorsum of the foot; through the space between the heads of the first muscle the deep plantar branch of the

dorsalis pedis artery In human anatomy, the dorsalis pedis artery (dorsal artery of foot) is a blood vessel of the lower limb. It arises from the anterior tibial artery, and ends at the first intermetatarsal space (as the first dorsal metatarsal artery and the deep pl ...

Origin

Insertion

Action

Innervation

Relations

See also

Additional images

Notes

References