Part 9: Posterior Compartment of Leg Flashcards
What is the skin innervation of posterior compartment?
Termination of posterior femoral cutaneous halfway down leg, below this Sural supplies back of calf, peroneal communicating nerves supply lateral and saphenous supplies medial
What is the origin, insertion, action and innervation of Gastrocnemius?
O: Lateral head - posterior surface lat condyle femur, medial head - posterior surface medial condyle of femur
I: TA - to middle of 3 facets on posterior aspect of calcaneus
A: Plantarflexion, flexion of knee
N: Tibial
What is the origin, insertion, action and innervation of plantaris
O: Lateral supracondylar ridge of femur above lat head of gastroc
I: TA (medial side deep to gastroc)
A: Vestigial muscle - plantarflexion and flexion of knee
N: Tibial
What is the origin, insertion, action and innervation of Soleus
O: Soleal line of tibia, middle 1/3 posterior border tibia, upper 1/4 of posterior shaft fibula including neck
I: TA - middle of 3 facets posterior surface of calcaneus
A: Plantarflexion
N: Tibial
What are the superficial muscles of the calf?
Gastrocnemius, Plantaris and soleus
How does the actions of soleus and gastrocnemius differ and how does their structure aid this?
Soleus - multipennate fibres, made for slow power. Mostly anti-gravity muscle maintaining balance and active in walking.
Gastrocnemius - vertical fibres, provide rapid whip like contraction. Most active in propulsion eg jumping. Action is greatly increased with simultaneous extension of flexed knee as fibres insert above knee joint therefore extending knee has direct pull on TA
What are the deep muscles of the calf?
Flexor digitorum longus
Flexor hallucis longus
Tibialis posterior
What is the origin, insertion, action and innervation of Flexor digitorum longus?
O: Posterior shaft tibia, below soleal line, with broad aponeurosis to fibula
I: Base distal phalanges of lateral 4 toes
A: flexion of DIPJ and secondary PIPJ flexion and plantarflexion. Helps maintain lateral longitudinal arch.
N: Tibial
What is the origin, insertion, action and innervation of flexor hallucis longus?
O: Lower 2/3 posterior fibula, lower IMS and IOM.
I: Base of distal phalanx of great toe
A: Flexion distal phalanx great toe, secondary plantarflexion. Supports longitudinal arch
N: Tibial
What is the origin, insertion, action and innervation of Tibialis posterior?
O: upper 1/2 posterior shaft tibia and upper 1/2 fibula
I: Tuberosity of navicular bone and via ligamentous expansions to other tarsal bones
A: Plantarflexion and inversion of foot. Supports medial longitudinal arch
N: Tibial
Describe the course of posterior tibial artery
Arises at lower border popliteus and tibial artery divides into A/P. Passes under fibrous arch of soleus runs vertically down between FDL and FHL. Ends under flexor retinaculum where it divides into M/L plantar arteries. Gives off nutrient branch to tibia and peroneal artery to lateral compartment
Describe the course of the tibial nerve
Runs straight down midline of calf, deep to soleus lying on fibular aponeurosis. Ends in flexor retinaculum with medial and lateral plantar nerves. It is the nerve of the flexor compartment.
