Anatomy - MOINA of the Posterior Fascial Compartment of the Leg

origin of gastrocnemius

• lateral head: from lateral epicondyle of femur

• medial head: from above medial condyle

insertion of gastrocnemius

via tendo calcaneus into posterior surface of calcaneum

innervation of gastrocnemius

tibial nerve

action of gastrocnemius

• plantar flexes foot at ankle joint

• flexes knee joint

origin of plantaris

lateral supracondylar ridge of femur

insertion of plantaris

posterior surface of calcaneum

innervation of plantaris

tibial nerve

action of plantaris

• plantar flexes foot at ankle joint

• flexes knee joint

origin of soleus

shafts of tibia and fibula

insertion of soleus

via tendo calcaneus into posterior surface of calcaneum

innervation of soleus

tibial nerve

action of soleus

• together with gastrocnemius and plantaris is powerful plantar flexor of ankle joint

• provides main propulsive force in walking and running

origin of popliteus

lateral surface of lateral condyle of femur

insertion of popliteus

posterior surface of shaft of tibia above soleal line

innervation of popliteus

tibial nerve

action of popliteus

• flexes leg at knee joint

• unlocks knee joint by lateral rotation of femur on tibia and slackens ligaments of joint

origin of flexor digitorum longus

posterior surface of shaft of tibia

insertion of flexor digitorum longus

bases of distal phalanges of lateral 4 toes

innervation of flexor digitorum longus

tibial nerve

action of flexor digitorum longus

• flexes distal phalanges of lateral 4 toes

• plantar flexes foot at ankle joint

• supports medial and lateral longitudinal arches of foot

origin of flexor hallucis longus

posterior surface of shaft of tibia

insertion of flexor hallucis longus

base of distal phalanx of big toe

innervation of flexor hallucis longus

tibial nerve

action of flexor hallucis longus

• flexes distal phalanx of big toe

• plantar flexes foot at ankle joint

• supports medial longitudinal arch of foot

origin of tibialis posterior

posterior surface of shafts of tibia and fibula and interosseus membrane

insertion of tibialis posterior

tuberosity of navicular bone and other neighboring bones

innervation of tibialis posterior

tibial nerve

action of tibialis posterior

• plantar flexes foot at ankle joint

• inverts foot at subtalar and transverse tarsal joints

• supports medial longitudinal arch of foot