Muscles of Leg

Muscles of the Leg (Calf) and Foot (and other important landmarks) Patella Head of the fibula Gastrocnemius Soleus Extensor digitorum longus Peroneus longus Tibialis anterior Tensor hallicus longus Peroneus brevis Flexor hallicus longus Peroneal retinaculum Lateral malleolus (“ankle bone”) Peroneus tertius Superior extensor retinaculum Inferior extensor retinaculum Muscles of Leg (Knee Down) l. Anterior Compartment of Leg (Knee Down) – Dorsiflexion (Extension) 1) Tibialis anterior (shin splints muscle) a. Actions: dorsiflexion, inverts foot (supports medial longitudinal arch) b. Innervation: Deep peroneal nerve c. Origin: from lateral condyle and upper tibia d. Insertion: to medial cuniform bone (tarsal) and 1st metatarsal bone 2) Extensor digitorum longus a. Actions: dorsiflexion, everts foot, extends toes b. Innervation: Deep peroneal nerve c. Origin: from lateral condyle and upper tibia and proximal fibula d. Insertion: to 2nd and 3rd phalanges of toes 2-5 3) Peroneus tertius a. Actions: dorsiflexion, everts foot b. Innervation: Deep peroneal nerve c. Origin: from distal and anterior fibula passes anterior to lateral malleolus d. Insertion: on the dorsum of the 5th metatarsal Patella Head of the fibula 7 8 1 5 Behind the knee, so not visible here. 10 Behind the knee, so 2 4) Extensor hallicus longus a. Actions: extends great toe, dorsiflexion of foot, aids in foot inversion b. Innervation: Deep peroneal nerve c. Origin: from anterior, medial fibula d. Insertion: to distal phalanx of big toe 9 not visible here. 11 On medial side, so not visible here. 6 13 Deep beneath soleus, so not visible here. 3 4 14 12 16 17 15 ll. Muscles of the Lateral Compartment of Leg (Knee Down) 5) Peroneus longus a. Actions: plantar flexion, everts foot b. Innervation: Superficial peroneal nerve c. Origin: from proximal fibula passes under foot d. Insertion: to 1st metatarsal 6) Peroneus brevis a. Actions: plantar flexion, everts foot b. Innervation: Superficial peroneal nerve c. Origin: from distal fibula passes behind lateral malleolus d. Insertion: to insert proximally on 5th metatarsal Patella lll. Superficial Muscles of the Posterior Compartment of Leg (Knee Down) 7) Gastrocnemius a. Actions: plantar flexion (when knee is extended), weak flexor of knee when foot is dorsifexed b. Innervation: Tibial nerve c. Origin: from medal and lateral condyles of femur d. Insertion: to calcaneous via Achilles tendon (also called Calcaneal tendon) Head of the fibula 7 8 d. Insertion: to calcaneous via Achilles tendon (also called Calcaneal tendon) 9 Behind the knee, so not visible here. 10 Behind the knee, so 2 8) Soleus a. Actions: plantar flexion (at ankle) – locomotion muscle b. Innervation: Tibial nerve c. Origin: from tibia and fibula d. Insertion: to calcaneous via Achilles tendon (also called Calcaneal tendon) 9) Plantaris a. Actions: assists in knee flexion, plantar flexion of foot b. Innervation: Tibial nerve c. Origin: from posterior femur laterally 1 5 not visible here. 11 On medial side, so not visible here. 6 13 Deep beneath soleus, so not visible here. 3 4 14 12 16 17 15 lV. Deep Muscles of the Posterior Compartment of Leg (Knee Down) 10) Popliteus a. Actions: flexes knee and rotates leg medially to unlock knee from full extension b. Innervation: Tibial nerve c. Origin: from lateral condyles of femur d. Insertion: to proximal tibia 11) Flexor digitorum longus a. Actions: plantar flexes foot, inverts foot, flexes toes (helps foot grip ground) b. Innervation: Tibial nerve c. Origin: from posterior tibia runs behind medial malleolus d. Insertion: into 4 tendons to distal phalanges of toes 2-5 12) Flexor hallicus longus a. Actions: plantar flexes foot, inverts foot, flexes big toe at all joints (pushes off during walking) b. Innervation: Tibial nerve c. Origin: from middle fibula runs under foot d. Insertion: to distal phalanx of big toe 13) Tibialis posterior a. Actions: inverts foot, plantar flexes foot (supports medial longitudinal arch) b. Innervation: Tibial nerve c. Origin: from proximal tibia and fibula it runs behind medial malleolus under arch d. Insertion: into 4 tendons to tarsals and metatarsals 2-4 Not Muscle: 14) Superior extensor retinaculum 15) Inferior extensor retinaculum 16) Peroneal retinaculum 17) Lateral malleolus or “ankle bone” Patella Head of the fibula 7 8 1 5 9 Behind the knee, so not visible here. 10 Behind the knee, so 2 not visible here. 11 On medial side, so not visible here. 6 13 Deep beneath soleus, so not visible here. 3 4 14 12 16 17 15