Posterior compartment of leg

The posterior compartment of the leg is one of the fascial compartments of the leg and is divided further into deep and superficial compartments.

Structure

Muscles

Superficial posterior compartment

Image	Muscle	Origin	Insertion	Innervation	Main Action !
File:Posterior compartment of leg - gastrocnemius.png	Gastrocnemius	Lateral head: lateral aspect of lateral condyle of femur Medial head: popliteal surface of femur; superior to medial condyle	Posterior surface of calcaneus via calcaneal tendon	Tibial nerve (S1, S2)	Plantarflexes ankle when knee is extended; raises heel during walking; flexes leg at knee joint
File:Posterior compartment of leg - plantaris.png	Plantaris	Inferior end of lateral supracondylar line of femur; oblique popliteal ligament			Weakly assists gastrocnemius in plantarflexing ankle
File:Posterior compartment of leg - soleus.png	Soleus	Posterior aspect of head and superior quarter of posterior surface of fibula; soleal line and middle third of medial border of tibia; and tendinous arch extending between the bony attachments			Plantarflexes ankle independent of position of knee; steadies leg on foot

Deep posterior compartment

Image	Muscle	Origin	Insertion	Innervation	Main Action
File:Posterior compartment of leg - flexor hallucis longus.png	Flexor hallucis longus muscle	Inferior two-thirds of posterior surface of fibula; inferior part of interosseous membrane	Base of distal phalanx of big toe (hallux)	Tibial nerve (S1, S2)	Flexes big toe at all joints; weakly plantarflexes ankle; supports medial longitudinal arch of foot
File:Posterior compartment of leg - tibialis posterior.png	Tibialis posterior muscle	Interosseous membrane; posterior surface of tibia inferior to soleal line; posterior surface of fibula	Tuberosity of navicular, cuneiform, cuboid, and sustentaculum tali of calcaneus; bases of 2nd, 3rd, and 4th metatarsals	Tibial nerve (L4, L5)	Plantarflexes ankle; inverts foot
File:Posterior compartment of leg - flexor digitorum longus.png	Flexor digitorum longus muscle	Medial part of posterior surface of tibia; by a broad tendon to fibula	Bases of distal phalanges of lateral four digits	Tibial nerve (S1, S2)	Flexes lateral four digits; plantarflexes ankle; supports longitudinal arches of foot
File:Posterior compartment of leg - popliteus muscle.png	Popliteus muscle	Lateral surface of lateral condyle of femur and lateral meniscus	Animation. Posterior surface of tibia, superior to soleal line	Tibial nerve (L4, L5, S1)	Weakly flexes knee and unlocks it by rotating femur 5 deg on fixed tibia; medially rotates tibia of unplanted limb

Blood supply

Posterior tibial artery

Innervation

The posterior compartment of the leg is supplied by the tibial nerve.

Function

• It contains the plantar flexors:

Additional images

• Superficial posterior compartment. Animation.
  Superficial posterior compartment. Animation.
• Deep posterior compartment. Animation.
  Deep posterior compartment. Animation.

External links

• Diagram at patientcareonline.com