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Muscles/Lower Leg

Lower Leg

popliteus

pop-LIT-ee-us

The popliteus is a small knee muscle behind the joint that 'unlocks' the knee from full extension for flexion. Crucial for downhill running and pivoting in sports. Prevents knee hyperextension.

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Common Pain & Injury

Pain behind knee from twisting; doctor if locking or swelling.

Anatomy & Function

Origin

Posterior surface of tibia and lateral condyle of femur (back shin bone and thigh bone)

Insertion

Posterior triangle of knee joint (inside knee capsule)

Actions

  • Knee flexion (bending knee)
  • Internal rotation of tibia (inward shin turn)

Innervation

Tibial nerve (L4-S1)

Muscle Relationships

Antagonists

Tensor fasciae latae

Synergists

SemimembranosusSemitendinosus

Trigger Points

Muscle belly refers to posteromedial knee and calf.

Stretches

1Popliteus figure-four stretch
2Kneeling knee bend
3Posterior knee glide

Common Conditions

Popliteus tendinopathyPosterolateral corner injury

Anatomical Parts

Left popliteusRight popliteus

FAQ

Popliteus muscle pain?

Behind-knee ache from running downhill or twisting.

What does popliteus do?

Unlocks knee and initiates flexion with rotation.

Popliteus tear?

Rare; causes instability and pain with pivots.

Strengthen popliteus?

Prone knee hangs with rotation.

Exercises for popliteus

20

Also Works popliteus

10

Related Lower Leg Muscles

extensor digitorum longus
The extensor digitorum longus runs lateral shin from knee to foot, extending toes 2-5 and dorsiflexing ankle. Builds shin definition for runners.
extensor hallucis longus
The extensor hallucis longus runs down the front of the lower leg and extends the big toe while also assisting in dorsiflexion of the ankle. It's crucial for clearing the foot during the swing phase of gait in runners and athletes. Strong EHL prevents foot drop and enhances explosive movements like jumping.
fibularis brevis
The fibularis brevis, aka peroneus brevis, lies low on the outer lower leg and everts the foot while plantarflexing it. It's essential for lateral stability in running, surfing, or agility drills. Fitness athletes strengthen it to prevent ankle rolls.
fibularis longus
The fibularis longus runs along the outer lower leg, crossing under the foot to evert and stabilize the arch. It powers push-off in sprinting and side-to-side movements. Crucial for runners to avoid ankle sprains and maintain foot alignment.
fibularis tertius
The fibularis tertius is a small muscle on the front-outer lower leg that assists in dorsiflexion and eversion. It's active in quick foot lifts during running or hiking. Often absent, but when present, aids ankle agility in sports.
flexor digitorum longus
The flexor digitorum longus is a powerful muscle in the deep posterior compartment of the lower leg, running from the tibia down to the toes. It flexes the four smaller toes and assists in plantarflexion at the ankle, helping with push-off during walking, running, and jumping. Strong flexors like this are crucial for balance, propulsion, and preventing foot drop in athletes.
flexor hallucis longus
Running deep in the calf's posterior compartment, the flexor hallucis longus flexes the big toe and plantarflexes the ankle. It's essential for powerful push-off in sprinting, ballet, and hill running. Athletes rely on it for toe grip on uneven terrain.
gastrocnemius
The gastrocnemius forms the visible calf bulge, crossing knee and ankle for explosive plantarflexion. Key for sprinting, jumping, and calf raises. Two heads make it powerful for athletic propulsion.

Lower Leg Pain Guide

Common causes and relief

Activities & Sports

See which activities use popliteus

Pinpoint·Interactive 3D Anatomy & Exercise Guide