Muscles - Posterior Leg

Question 1

Which muscles are located in the posterior leg?

Answer 1

1. Popliteus
2. Gastrocnemius
3. Soleus
4. Plantaris
5. Tibialis posterior
6. Flexor digitorum longus
7. Flexor hallucis longus

Question 2

Which nerve innervates the muscles in the posterior leg?

Answer 2

Tibial nerve (division of sciatic nerve L4-S3)

Question 3

Describe the anatomy of the calf muscles

Answer 3

1. Gastrocnemius
   PA: lateral head - lateral condyle of femur; medial head - popliteal surface of femur (superior to medial condyle)
   DA: posterior calcaneus via Achilles tendon
   Action: plantarflexion of ankle when knee is extended, raises heel when walking, flexes the knee
2. Soleus:
   PA: fibula (posterior head and superior posterior surface), tibia (middle third of medial tibial border), and tendinous arch extending between bony attachments
   DA: posterior calcaneus via Achilles tendon
   Action: plantarflexion of ankle

Innervation: tibial nerve (L4-S3)

Question 4

Describe the anatomy of tibialis anterior

Answer 4

PA: posterior tibia (inferior to soleal line), posterior fibula and interosseous membrane

DA: navicular tuberosity, cuneiforms, cuboid, base of mets 2-3-4, and sustentaculum tali of calcaneus

Action: plantarflexes ankle, inverts foot, supports medial longitudinal arch

N: tibial (L4-S3)

Question 5

Describe the anatomy of plantaris

Answer 5

PA: femur (lateral supracondylar line) and oblque popliteal ligament

DA: posterior calcaneus via calcaneal tendon

Action: weakly assists gastrocs in plantarflexing ankle and flexing knee

N: tibial (L4-S3)

Question 6

Describe the anatomy of popliteus

Answer 6

PA: lateral condyle of femur, lateral meniscus

DA: posterior tibia (superior to soleal line)

Action: lateral rotation of femur, medial rotation of tibia when knee is flexed, flexion of knee (weak)

N: tibial (L4-S3)

Question 7

Describe the anatomy of flexor digitorum longus

Answer 7

PA: medial posterior tibia (inferior to soleal line), via broad tendon to fibula

DA: base of distal phalanges of digits 2-5

Action: flexes digits 2-5, plantarflexes ankle, supports longitudinal arches of foot

N: tibial (L4-S3)

Question 8

Describe the anatomy of flexor hallucis longus

Answer 8

PA: posterior fibula (inferior two thirds) and interosseous membrane

DA: base of distal phalanx of digit 1

Action: flexes digit 1, weak ankle plantarflexor, supports medial arch of foot

N: tibial (L4-S3)