Posterior Crural Muscles

Question 1

Flexor digitorum longus

Answer 1

(L5-S2)

attachments- from the posterior tibia distal to the soleal line to the plantar surface of the distal phalangeal bases digits 2-5

actions- plantar flexes ankle, and flexes digits 2-5 (MP & IP)

innervation- tibial nerve

Question 2

Flexor hallucis longus

Answer 2

(L5-S2)

attachments- from the distal 2/3rds of the posterior fibula & crural interosseous membrane to the plantar aspect of the distal phalangeal base of the 1st toe

actions- plantar flexes ankle, and flexes great toe (MP & IP)

innervation- tibial nerve

Question 3

Gastrocnemius

Answer 3

(S1-2)

attachments- from the posterior aspect of the femoral condyles and joint capsule to the posterior calcaneal surface

actions- flexes knee, and plantar flexes ankle

innervation- tibial nerve

Question 4

Plantaris

Answer 4

(L4-S1)

attachments- from the lateral supracondylar ridge to the posterior calcaneal surface

actions- flexes knee, and plantar flexes ankle

innervation- tibial nerve

Question 5

Popliteus

Answer 5

(L4-S1)

attachments- from the lateral femoral condyle and oblique popliteal ligament to the soleal line of the tibia

actions- in NWB, medial rotation of tibia and knee flexion; in WB insertion is fixed: lateral rotation of femur and knee flexion; thus, it unlocks the knee from extension into early flexion

innervation- tibial nerve

Question 6

Soleus

Answer 6

(L5-S2)

attachments- from the posterior aspect of the head & proximal 1/4th of the fibula & tibial soleal line to the posterior calcaneal surface

actions- plantar flexes the foot at the ankle joint

innervation- tibial nerve

Question 7

Tibialis posterior

Answer 7

(L4-S1)

attachments- from the crural interosseous membrane, lateral tibial surface & medial fibular surface to the navicular, medial & intermediate cuneiforms and bases of metatarsals 2-4

actions- inverts foot and plantar flexes ankle

innervation- tibial nerve