foot and ankle myology

Question 1

muscles in the anterior compartment of lower leg

Answer 1

tibialis anterior, extensor digitorum longus, extensor hallucis longus

Question 2

tibialis anterior

Answer 2

*Origin- upper ½ Lateral surface of tibia and adjacent interosseous membrane
*Insertion- Medial surface of medial cuniform and base of 1st metatarsal.
*Action- Dorsiflexor of ankle
-In conjunction with tibialis posterior it inverts the foot

Question 3

extensor digitorum longus

Answer 3

*Origin- Upper 2/3 anterior fibula and interosseous membrane
*Insertion- via the extensor hood into bases of distal and middle phalanges of lateral 4 toes
*Action- Extends lateral 4 toes at MTP Jts & assists at IP Jts
-Aids dorsiflexion.

Question 4

extensor hallucis longus

Answer 4

*Origin- Anterior surface of middle half of fibula & interosseous membrane.
*Insertion- dorsal surface of base of distal phalanx of great toe.
*Action- Extends all the joints of the 1st toe (mainly MTP Jt).
-Dorsiflexor of ankle (weak).
-Weak inversion/eversion

Question 5

muscles in the lateral compartment of lower leg

Answer 5

peroneus (fibularis) longus + peroneus (fibularis) brevis

Question 6

peroneus (fibularis) longus

Answer 6

*Origin- Upper 2/3 of lateral fibula & fibula head.
*Insertion- medial cuneiform and base of 1st metatarsal.
*Action- Eversion of the foot.
- Plantarflexor of the ankle.
- Some pronation.

Question 7

peroneus (fibularis) brevis

Answer 7

*Origin- lower 2/3 lateral fibular surface.
*Insertion- a tubercle on the 5th metatarsal
*Action- Eversion of the foot.
- Plantarflexion of the ankle simultaneously.
- balance; sideways correction.

Question 8

muscles in the posterior compartment of lower leg (superficial)

Answer 8

gastrocnemius, soleus + (plantaris)

Question 9

gastrocnemius

Answer 9

*Origin- posterior aspect of medial & lateral femoral condyles (medial and lateral heads)
*Insertion- achilles tendon
*Action- weak knee flexor, plantaflexion of ankle

Question 10

soleus

Answer 10

*Origin- soleal line on posterior tibial surface, posterior surface upper 1/3 fibula.
*Insertion- tendon fuses with gastroc tendon to form tendocalcaneus (achilles tendon)
- Inserting into middle/ posterior calcaneus.
*Action- Plantarflexes ankle

Question 11

muscles in the posterior compartment of lower leg (deep)

Answer 11

tibialis posterior, flexor digitorum longus, flexor hallucis longus

Question 12

tibialis posterior

Answer 12

*Origin- posterior surface of interosseous membrane & adjacent regions of tibia (below soleal line) & fibula.
*Insertion- tuberosity of navicular & medial cuneiform with expansions to all tarsal bones except talus.
*Action- Inversion of foot
- Plantarflexion of ankle

Question 13

flexor digitorum longus

Answer 13

*Origin- Medial side of posterior surface of the tibia
*Insertion- Bases of distal phalanges 2-5th toes.
*Action- Flexes lateral 4 toes.
- DIP first then PIP & lastly MTP.
- Plantarflexor of ankle (weak).

Question 14

flexor hallucis longus

Answer 14

*Origin- middle 1/3 of posterior fibula surface & interosseous membrane.
*Insertion- base of distal phalanx of great toe.
*Action- Flexes all joints of great toe. Firstly IPJ then MTP Jt.
- Plantarflexion of ankle.