Muscles of the Leg

What is the insertion of the soleus muscle?

Calcaneal tendon (makes up posterior aspect)

What is the insertion of the plantaris muscle?

Can attach by the calcaneal tendon, or directly into the posterior, medial calcaneus.

What is the action of the extensor digitorum longus?

Controls the extensor expansion of the foot. Extends MTP joints, and by continued action: dorsiflexes the ankle, and everts the foot.

What nerve innervates the peroneus tertius muscle, and what is its primary myotome?

Deep peroneal nerve (L5 & S1).

What is the insertion of the flexor digitorum longus?

Divides into four tendons, which attach to the base of the plantar surface of the four lateral digits.

What is the action of the tibialis anterior?

Dorsiflexion of the ankle joint, and inversion of the foot.

What is the action of the peroneus longus?

Eversion and plantar flexion of the foot (simultaneously).

What is the action of the peroneus tertius?

Eversion of foot, and dorsiflexion of the ankle. (everts as it dorsiflexes).

What is the action of the pernoneus brevis?

Everts foot, and plantar flexes ankle by continued action.

What is the insertion of the politeus muscle?

Exits joint capsule and attaches to posterior proximal border of the tibia.

What is the action of the extensor hallucis longus?

Extends the IP joints of the ankle, and by continued action: extends the MTP, and ankle joint. Assists other muscles in inversion of the foot.

What is the action of the flexor digitorum longus?

Flexes DIP, and by continued action: flexes PIP, MTP, and ankle (plantar flexion). Assists tibialis posterior and other muscles in inversion.

What is the action of the flexor hallucis longus?

Flexion of the PIP of hallux, and through continued action: flexion of MTP, inversion of the foot, and flexion of the ankle.

What is the action of the politeus muscle?

Initiates knee flexion by medially rotating the knee slightly in order to break the conformity of the splinted knee.

What is the action of the tibialis posterior?

Inverts foot and assists gastrocnemius and soleus in plantarflexion of foot.

How can the flexor hallucis longus be easily identified?

It becomes tendonis more distally than any of the other flexor muscles.

What is the major function (not action) of the peroneus longus?

Keeps the plantar medial portion of the foot on the ground during ambulation, and it holds the transverse arch of the foot in its proper position.

Which is an important function (not action) of the gastrocnemius?

Knee stability.

What is the origin of the plantaris muscle?

Lateral condyle of femur.

What is the origin of the extensor digitorum longus muscle?

Lateral condyle of tibia, and proximal 3/4 of anterior aspect of fibular shaft, and the adjacent interosseus membrane.

What is the origin of the gastrocnemius?

Medial and lateral supracondylar ridges.

What is the origin of the flexor digitorum longus?

Mid-shank level of posterior tibia.

What is the insertion of the tibialis posterior?

Plantar, medial side of foot.

What is the action of the soleus?

Plantarflexes foot.

What is the action of the plantaris muscle?

Plantarflexion of the ankle, and flexion of the knee joint. (performs both actions weakly).

What is the action of the gastrocnemius muscle?

Plantarflexion, slight inversion of the foot, and flexion of the knee.

What action can a muscle perform if it is considered an "anti-gravity" muscle?

Plantarflexion.

What is the origin of the tibialis posterior?

Posterior proximal leg.

What is the origin of the soleus muscle?

Proximal, posterior surface of fibula and tibia.

What is the insertion of the gastrocnemius?

Tendon expansion into middle posterior surface of calcaneus.

What nerve innervates the flexor digitorum longus, and what is the muscle's primary myotome(s)?

The Tibial Nerve (S2).

What is the origin of the extensor hallucis longus?

The anterior distal shaft of the fibula, and the interosseus membrane.

What is the insertion of the flexor hallucis longus?

The base of the plantar surface of the distal phalanx of the hallux.

What nerve innervates the extensor digitorum longus, and what is the muscle's primary myotome?

The deep peroneal nerve (L5 & S1)

What nerve innervates the extensor hallucis longus, and what are the muscle's primary myotome(s)?

The deep peroneal nerve. (L5 & S1).

What is nerve innervates the tibialis anterior, and what is the muscle's primary myotome(s)?

The deep peroneal/ anterior tibial nerve. (L4).

What is the origin of the peroneus tertius?

The distal anterior fibula, interosseus membrane, and extensor digitorum longus.

What is the insertion of the extensor hallucis longus?

The dorsal proximal base of the distal phalanx of the hallux.

What is the insertion of the peroneus tertius?

The dorsal surface of the cuboid/ 5th metatarsal.

What muscle is the peroneus tertius analogous to in the upper extremity?

The extensor digiti minimi.

What muscle is the extensor digitorum longus analogous to in the upper extremity?

The extensor digitorum (communis).

What muscle is the flexor digitorum longus analogous to in the upper extremity?

The flexor digitorum profundus.

What muscle is the flexor hallucis longus analogous to in the upper extremity?

The flexor pollicis longus.

What are the 3 muscles of the superficial posterior compartment of the leg from superficial to deep?

The gastrocnemius, the soleus, and the plantaris.

Which muscle of the superficial posterior compartment of the shank is biarticular?

The gastrocnemius.

What is the insertion of the peroneus longus?

The lateral aspect of the base of the 1st metatarsal, and medial cuneiform.

What is the insertion of the peroneus brevis?

The lateral aspect of the tuberosity of the base of the 5th metatarsal.

What is the origin of the politeus muscle?

The lateral condyle of the femur within the joint capsule.

What is the insertion of the tibialis anterior?

The medial plantar surface of the navicular bone, and some of the 1st cuneiform.

What is the origin of the peroneus brevis?

The middle, lateral fibula.

What muscles are found in the lateral compartment of the shank?

The peroneus longus and brevis.

Which muscle of the superficial posterior compartment of the shank is important for surgery, and why?

The plantaris muscle can be harvested for use in surgery in another part of the body as it does not have a major role in leg function.

What is the insertion of the extensor digitorum longus?

The posterior aspects of the base of the 2nd and 3rd phalanges of the lesser toes.

What is the origin of the flexor hallucis longus?

The posterior middle shaft of the fibula.

What is the origin of the tibialis anterior?

The proximal anterior tibia.

What is the origin of the peroneus longus?

The proximal lateral fibula.

What nerve innervates the peroneus brevis, and what is the muscle's primary mytome(s)?

The superficial peroneal nerve (S1).

What nerve innervates the peroneus longus, and what is the muscle's primary myotome?

The superficial peroneal nerve. (S1).

What nerve innervates the politeus muscle, and what is the muscle's primary myotomes?

The tibial nerve (L4 & L5).

What nerve innervates the tibialis posterior, and is its primary myotome(s)?

The tibial nerve (L4 & L5).

What nerve innervates the flexor hallucis longus, and what is the primary myotome of the muscle?

The tibial nerve (S2).

What nerve innervates the plantaris muscle, and what is its primary myotome?

The tibial nerve (S2).

What nerve innervates the soleus, and what is its primary myotome?

The tibial nerve. (S2)

What nerve innervates the gastrocnemius, and what is its primary myotome?

Tibial Nerve (S2).