Editing Human leg (section)

===== Intrinsic =====
The intrinsic muscles of the foot, muscles whose bellies are located in the foot proper, are either dorsal (top) or plantar (sole).
On the dorsal side, two long extrinsic extensor muscles are superficial to the intrinsic muscles, and their tendons form the dorsal aponeurosis of the toes. The short intrinsic extensors and the plantar and dorsal interossei radiates into these aponeuroses. The [[Extensor digitorum brevis muscle|extensor digitorum brevis]] and [[Extensor hallucis brevis muscle|extensor hallucis brevis]] have a common origin on the anterior side of the calcaneus, from where their tendons extend into the dorsal aponeuroses of digits 1–4. They act to dorsiflex these digits.<ref>Platzer (2004), p. 268</ref>

The plantar muscles can be subdivided into three groups associated with three regions: those of the big digit, the little digit, and the region between these two. All these muscles are covered by the thick and dense [[plantar aponeurosis]], which together with two tough septa, form the spaces of the three groups. These muscles and their fatty tissue function as cushions that transmit the weight of the body downward. As a whole, the foot is a functional entity.<ref name="Platzer-270">Platzer (2004), p. 270</ref>

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The [[Abductor hallucis muscle|abductor hallucis]] stretches along the medial edge of the foot, from the calcaneus to the base of the first phalanx of the first digit and the medial sesamoid bone. It is an abductor and a weak flexor, and also helps maintain the arch of the foot. Lateral to the abductor hallucis is the [[Flexor hallucis brevis muscle|flexor hallucis brevis]], which originates from the medial cuneiform bone and from the tendon of the tibialis posterior. The flexor hallucis has a medial and a lateral head inserted laterally to the abductor hallucis. It is an important plantar flexor which comes into prominent use in [[classical ballet]] (i.e. for [[en pointe|pointe work]]).<ref name="Platzer-270" /> The [[Adductor hallucis muscle|adductor hallucis]] has two heads; a stronger oblique head which arises from the cuboid and lateral cuneiform bones and the bases of the second and third metatarsals; and a transverse head which arises from the distal ends of the third-fifth metatarsals. Both heads are inserted on the lateral sesamoid bone of the first digit. The muscle acts as a tensor to the arches of the foot, but can also adduct the first digit and plantar flex its first phalanx.<ref name="Platzer-272">Platzer (2004), p. 272</ref>

The [[Opponens digiti minimi muscle|opponens digiti minimi]] originates from the long plantar ligament and the plantar tendinous sheath of the fibularis (peroneus) longus and is inserted on the fifth metatarsal. When present, it acts to plantar flex the fifth digit and supports the plantar arch. The [[Flexor digiti quinti brevis muscle (foot)|flexor digiti minimi]] arises from the region of base of the fifth metatarsal and is inserted onto the base of the first phalanx of the fifth digit where it is usually merged with the abductor of the first digit. It acts to plantar flex the last digit. The largest and longest muscles of the little toe is the [[Abductor digiti quinti muscle (foot)|abductor digiti minimi]]. Stretching from the lateral process of the calcaneus, with a second attachment on the base of the fifth metatarsal, to the base of the fifth digit's first phalanx, the muscle forms the lateral edge of the sole. Except for supporting the arch, it plantar flexes the little toe and also acts as an abductor.<ref name="Platzer-272" />

The four [[Lumbrical muscle (foot)|lumbricales]] have their origin on the tendons of the flexor digitorum longus, from where they extend to the medial side of the bases of the first phalanx of digits two-five. Except for reinforcing the plantar arch, they contribute to plantar flexion and move the four digits toward the big toe. They are, in contrast to the lumbricales of the hand, rather variable, sometimes absent and sometimes more than four are present. The [[quadratus plantae]] arises with two slips from margins of the plantar surface of the calcaneus and is inserted into the tendon(s) of the flexor digitorum longus, and is known as the "plantar head" of this latter muscle. The three [[Plantar interossei muscles|plantar interossei]] arise with their single heads on the medial side of the third-fifth metatarsals and are inserted on the bases of the first phalanges of these digits. The two heads of the four [[Dorsal interossei muscles (foot)|dorsal interossei]] arise on two adjacent metatarsals and merge in the intermediary spaces. Their distal attachment is on the bases of the proximal phalanges of the second-fourth digits. The interossei are organized with the second digit as a longitudinal axis; the plantars act as adductors and pull digits 3–5 towards the second digit; while the dorsals act as abductors. Additionally, the interossei act as plantar flexors at the [[metatarsophalangeal joint]]s. Lastly, the [[Flexor digitorum brevis muscle|flexor digitorum brevis]] arises from underneath the calcaneus to insert its tendons on the middle phalanges of digit 2–4. Because the tendons of the flexor digitorum longus run between these tendons, the brevis is sometimes called ''perforatus''. The tendons of these two muscles are surrounded by a tendinous sheath. The brevis acts to plantar flex the middle phalanges.<ref>Platzer (2004), p. 274</ref>
{{See also|Table_of_muscles#Leg|l1=Table of muscles}}