Leg bones and muscles

Question 1

Describe the shape of the tibial shaft?

Answer 1

Triangular in cross section

Question 2

Describe the surfaces of the tibia, and the important features of each?

Answer 2

Medial, lateral and posterior surfaces

Medial surface is subcutaneous

Posterior surface - soleal line

Question 3

What does the soleal line delineate?

Answer 3

Attachment of soleus and popliteus

Question 4

Which muscular compartments are present in the leg?

What are their actions?

Answer 4

Anterior compartment: dorsiflex foot, extend toes

Posterior compartment: plantarflex foot, flex toes

Lateral compartment: evert foot

Question 5

Describe the fascia that creates the three muscular compartments of the leg?

Answer 5

Deep fascia continuous with fascia lata - attached directly to tibia

Pair of intermuscular septa (anterior and posterior) arise from deep fascia to divide into three compartments

Interosseous membrane also contributes to divisions

Question 6

Describe the arrangement of the muscle compartments in the leg?

Answer 6

Anterior

Lateral

Posterior (deep) - mirror of anterior

Posterior (deep)

Question 7

List the muscles in the anterior compartment of the leg?

Answer 7

Tibialis anterior

EDL

EHL

(Fibularis tertius)

Question 8

Describe the borders of the anterior compartment of the leg?

Answer 8

Between tibia, interosseous membrane, anterior intermuscular septum and deep fascia

Question 9

Describe the actions of the muscles in the anterior compartment of the leg?

Answer 9

DORSIFLEXION AND EXTEND TOES

Tibialis anterior: dorsiflexion and inversion (on medial side of foot)

EDL: extends smaller toes

EHL: extends big toe

Question 10

Why is tibialis anterior important in inversion?

Answer 10

Inserts on medial side of foot

(medial cuneifrom and base of first metatarsal)

Question 11

Describe the insertion of tibialis anterior?

Answer 11

Medial cuneiform and base of first metatarsal

Question 12

Describe the fibularis tertius muscle?

Answer 12

Spilts off from EDL

Small tendon

Inserts into base of fifth metatarsal

Question 13

Describe the arrangement of muscles on the dorsum of the foot?

Answer 13

Run under extensor retinaculum

TIMOTHY HAS A NASTY DIRTY TOE

Medial to lateral: tibialis anterior, EHL, anterior tibial artery, deep fibular nerve, EDL, fibularis tertius

Question 14

List the muscles in the lateral compartment of the leg?

Answer 14

Fibularis longus

Fibularis brevis

Question 15

Describe the boundaries of the lateral compartment of the leg?

Answer 15

Between anterior and posterior septa, deep fascia and fibula

Question 16

Describe the actions of the muscles in the lateral compartment of the leg?

Answer 16

Eversion

Question 17

Describe the pathway of the fibularis longus muscle?

Answer 17

Proximal shaft of fibula > beneath sole of foot > tendon grooves cuboid bone > medial insertion: medial cuneiform and base of first metatarsal

Question 18

Describe the insertion of fibularis brevis?

Answer 18

Base of fifth metatarsal

Question 19

Describe the arrangement of the fibularis longus and brevis muscles as they pass along the side of the foot?

Answer 19

Pass behind lateral malleolus (brevis grooves the bone)

Question 20

List the muscles of the superficial posterior compartment of the leg?

Answer 20

Gastrocnemius

Soleus

(Popliteus)

(Plantaris)

Question 21

Describe the plantaris muscle?

Answer 21

Short belly, long slender tendon > vestigial

Question 22

Describe the realtionhip of the plantaris muscle to gastrocnemius?

Answer 22

Lies edge to edge with lateral head

Disappears from view as it passes behind medial head

Question 23

Describe the gastrocnemius muscle?

Answer 23

Two fleshy bellies

One from each condyle of femur

Comon tendon of insertion - achilles

Question 24

Describe the origin of the soleus muscle?

Answer 24

Arises from soleal line

Oblique line with fibrous arch

Horseshoe shape origin across both tibia and fibula

Question 25

Other than movements of the ankle joint, what is the important function of soleus?

Answer 25

Muscular pump

Question 26

List the muscles in the deep posterior compartment of the leg?

Answer 26

Tibialis posterior FHL FDL

Question 27

Describe the actions of the muscles in the deep posterior compartment of the leg?

Answer 27

Tibialis posterior: plantarflexion and inversion FDL: flexes little toes FHL: flexes big toe

Question 28

Describe how inversion of the foot is achieved?

Answer 28

Contraction of both tibialis anterior and tibialis posterior

Question 29

Describe the insertion of tibialis posterior?

Answer 29

Medial cunieform and base of first metatarsal (same as tibialis anterior)

Question 30

Describe the arrangement of structures that pass beneath the flexor retinaculum?

Answer 30

TOM DICK AND VERY NAUGHTY HARRY Medial malleolus to calcaneus: Tibialis posterior, FDL, posterior tibial artery, posterior tibial vein, tibial nerve, FHL

Question 31

Describe how FDL and FHL are positioned relative to each other along their pathways?

Answer 31

FDL tendon lies above FHL tendon in flexor retinaculum FDL passes over FHL tendon to reach smaller toes