Editing Foot (section)

====Extrinsic====
[[File:Gray437.png|thumb|80px|Anterior leg muscles]]

All muscles originating on the lower leg except the [[popliteus muscle]] are attached to the bones of the foot. The tibia and fibula and the [[interosseous membrane of leg|interosseous membrane]] separate these muscles into anterior and posterior groups, in their turn subdivided into subgroups and layers.<ref name="Platzer-256">Platzer 2004, p. 256</ref>

=====''Anterior group''=====
''Extensor group'': the [[tibialis anterior muscle|tibialis anterior]] originates on the proximal half of the tibia and the [[interosseous membrane of leg|interosseous membrane]] and is inserted near the [[tarsometatarsal joint]] of the first digit. In the non-weight-bearing leg, the tibialis anterior dorsiflexes the foot and lift its medial edge ([[supination]]). In the weight-bearing leg, it brings the leg toward the back of the foot, like in rapid walking. The [[extensor digitorum longus muscle|extensor digitorum longus]] arises on the lateral tibial condyle and along the fibula, and is inserted on the second to fifth digits and proximally on the fifth metatarsal. The extensor digitorum longus acts similar to the tibialis anterior except that it also dorsiflexes the digits. The [[extensor hallucis longus muscle|extensor hallucis longus]] originates medially on the fibula and is inserted on the first digit. It dorsiflexes the big toe and also acts on the ankle in the unstressed leg. In the weight-bearing leg, it acts similarly to the tibialis anterior.<ref name="Platzer-258">Platzer 2004, p. 258</ref>

''Peroneal group'': the [[peroneus longus muscle|peroneus longus]] arises on the proximal aspect of the fibula and [[peroneus brevis muscle|peroneus brevis]] below it. Together, their tendons pass behind the lateral [[malleolus]]. Distally, the peroneus longus crosses the plantar side of the foot to reach its insertion on the first tarsometatarsal joint, while the peroneus brevis reaches the proximal part of the fifth metatarsal. These two muscles are the strongest pronators and aid in plantar flexion. The peroneus longus also acts like a bowstring that braces the transverse arch of the foot.<ref name="Platzer-260">Platzer 2004, p. 260</ref>

{{multiple image
| align = right
| image1 = Gray438.png
| width1 = 100
| alt1 = 
| caption1 = 
| image2 = Gray439.png
| width2 = 80
| alt2 = 
| caption2 = 
| footer = Deep and superficial layers of posterior leg muscles
}}

=====''Posterior group''=====
The ''superficial layer'' of posterior leg muscles is formed by the [[triceps surae muscle|triceps surae]] and the [[plantaris muscle|plantaris]]. The triceps surae consists of the [[soleus muscle|soleus]] and the two heads of the [[gastrocnemius muscle|gastrocnemius]]. The heads of gastrocnemius arise on the [[femur]], proximal to the condyles, and the soleus arises on the proximal dorsal parts of the tibia and fibula. The tendons of these muscles merge to be inserted onto the calcaneus as the [[Achilles tendon]]. The plantaris originates on the femur proximal to the lateral head of the gastrocnemius and its long tendon is embedded medially into the Achilles tendon. The triceps surae is the primary plantar flexor. Its strength becomes most obvious during ballet dancing. It is fully activated only with the knee extended, because the gastrocnemius is shortened during flexion of the knee. During walking it not only lifts the heel, but also flexes the knee, assisted by the plantaris.<ref name="Platzer-262">Platzer 2004, p. 262</ref>

In the ''deep layer'' of posterior muscles, the [[tibialis posterior muscle|tibialis posterior]] arises proximally on the back of the [[interosseous membrane of leg|interosseous membrane]] and adjoining bones, and divides into two parts in the [[Sole (foot)|sole of the foot]] to attach to the tarsus. In the non-weight-bearing leg, it produces plantar flexion and supination, and, in the weight-bearing leg, it proximates the heel to the calf. The [[flexor hallucis longus muscle|flexor hallucis longus]] arises on the back of the fibula on the lateral side, and its relatively thick muscle belly extends distally down to the [[flexor retinaculum of foot|flexor retinaculum]] where it passes over to the medial side to stretch across the sole to the distal phalanx of the first digit. The [[popliteus muscle|popliteus]] is also part of this group, but, with its oblique course across the back of the knee, does not act on the foot.<ref name="Platzer-264">Platzer 2004, p. 264</ref>