Muscles of the Posterior Leg

Question 1

Superficial muscles

Answer 1

Gastrocnemius
Plantaris
Soleus

Question 2

Deep muscles

Answer 2

Popliteus
Tibialis posterior
Flexor digitorum longus
Flexor hallucis longus

Question 3

Gastrocnemius

Answer 3

• Origin - lateral head - lateral femoral condyle / medial head - medial femoral condyle
• Attachment - calcaneus
• Actions - plantarflexes at ankle joint, flexes knee
• Innervation - tibial nerve

Question 4

Plantaris

Answer 4

• Origin - lateral supracondylar line of femur
• Attachment - blends with calcaneal tendon
• Actions - plantarflexion at ankle joint, flexion of knee (not vital for these movements)
• Innervation - tibial nerve

Question 5

Soleus

Answer 5

• Origin - soleal line of the tibia and proximal fibular area
• Attachment - joins the calcaneal tendon
• Actions - plantarflexes the foot at the ankle joint
• Innervation - tibial nerve

Question 6

Popliteus

Answer 6

• Origin - posterior surface of proximal tibia
• Attachment - lateral condyle of the femur
• Actions - lateral rotation of the femur on the tibia, unlocking the knee joint so flexion can occur
• Innervation - tibial nerve

Question 7

Tibialis posterior

Answer 7

• Origin - interosseous membrane between tibia and fibula and posterior surfaces of the two bones
• Attachment - plantar surface of the medial tarsal bones
• Actions - inverts and plantarflexes the foot, maintains the medial arch of the foot
• Innervation - tibial nerve

Question 8

Flexor digitorum longus

Answer 8

• Origin - medial surface of the tibia
• Attachment - plantar surfaces of the lateral four digits
• Actions - flexes the lateral four toes
• Innervation - tibial nerve

Question 9

Flexor hallucis longus

Answer 9

• Origin - posterior surface of the fibula
• Attachment - plantar surface of the phalanx of the big toe
• Actions - flexes the big toe
• Innervation - tibial nerve

Question 10

Ruptured calcaneal tendon

Answer 10

Most likely in people with history of calcaneal tendinitis
Usually sustained during forceful plantarflexion of the foot
Patient unable to plantarflex foot against resistance -> affected foot will be permanently dorsiflexed
Soleus + gastrocnemius can contract -> form lump in calf
Treatment usually non-surgical, except in those with active lifestyles