Posterior Leg

overview of posterior leg muscles in terms of actions

plantar flexors, inverters, toeflexors

superficial compartment muscles

gastrocnemius, soleus, plantaris

deep posterior leg muscles

• popliteus

• tib post

• flexor digitorum longus

• flexor hallucis longus

what are all muscles in posterior leg innervated by

tibial nerve (L4-S3)

gastrocnemius O I A

LH: LATERAL FEMORAL CONDYLE

MH: medial femoral condyle

A: plantar flexor, knee flexion

gastrocnemius innervated by what

tibial nerve

Soleus

deep to gastroc

O: HEAD OF FIBULA, SOLEAL LINE OF TIBIA

I: CALCANEAL TENDON

A: PLANTAR FLEXION

soleus innervation

tibial nerve

two heads of gastrocnemius, and soleus coming together at calcaneal tendon is called what

triceps surae

where is calcaneal tendon inserting

calcaneal tuberosity

plantaris

O: lateral supracondylar line

I: calcaneal tendon

A: weakly assists plantar flexion

innervated by tibial nerve

what muscles are found in deep posterior leg region

popliteus

flexor digitorum longus

tibialis posterior

flexor hallucis longus

popliteus

Popliteus

▪ O: lateral femoral condyle +

lateral meniscus

▪ I: Posterior surface tibia

superior to Soleal line

▪ Action

– Rotates femur laterally to

unlock the knee (fixed tibia)

▪ Innervation

– Tibial n. (L4-S3)

flexor digitorum longus

O: distal posterior tibia

▪ I: distal phalanges 2-4

– Passes posterior to medial

malleolus to plantar surface

▪ Action

– Plantar flexion

– Flex digits 2-4 (MTP, PIP,

DIP)

– Inversion

▪ Innervation

– Tibial n. (L4-S3)

Tibialis posterior

O: tibia, interosseus

membrane, fibula

▪ I: tarsals, base of MT 2-4

– Passes posterior to medial

malleolus to plantar surface

▪ Action

– Inversion

– Plantar flexion

– Support arches

▪ Innervation

– Tibial n. (L4-S3)

flexor hallicus longus

Flexor hallucis longus

▪ O: posterior fibula,

interosseus membrane

▪ I: distal phalanges 1

– Passes posterior to medial

malleolus to plantar surface

▪ Action

– Flex hallux

– Plantar flexion

▪ Innervation

– Tibial n. (L4-S3)

structural relationships for msucles of the posterior leg

medially to laterally

(DOWN THE HATCH)

flexordigitorum longus, tibialis posterior, flexur hallucis longus

once these muscles travel posterior to the medial malleolus (tarsal tunnel) something happens, what would this structural relationship be?

TOM DICK HARRY

ant—-posterior

TP,FDL,FHL

Phase A → C: Lowering the heels

• This is ankle dorsiflexion, produced eccentrically by the triceps surae (gastrocnemius + soleus) as they lengthen to control the downward motion.

• The Achilles tendon is also being lengthened under load.

• The subtalar and midfoot joints contribute slight pronation depending on individual mechanics.

Phase C → A: Returning to neutral

• Still controlled plantarflexor activity, transitioning from eccentric to isometric as the ankle returns to a neutral position on the step.

Phase A → B: Rising onto the toes

• This is ankle plantarflexion, produced concentrically by the triceps surae.

• The movement lifts the body vertically by shortening the calf muscles and increasing tension through the Achilles tendon.

• The ankle may demonstrate slight supination as the heel rises (again depending on an individual's pattern).

Phase B → A: Lowering back to neutral

• Controlled eccentric dorsiflexion action of the plantarflexors.