musculoskeletal system

anatomy

muscles of foot sheet

done by: dina sawadha &

mohammad abukabeer

Extensor retinaculum :

A- superior extensor retinaculum (SER) : originates from the distal ends of the

tibia and fibula ( just proximal to medial and lateral malleoli )

B- inferior extensor retinaculum (IER) : Y shaped ligament , originates from

the lateral side of calcaneus and tarsal sinus , forms two bands ; superior

band that passes to the medial malleolus and inferior band that passes to the

navicular and medial cuneiform bone .

- IER functions in the fixation of the tendons of the extensor muscles and

peroneal nerve .

- deep peroneal nerve and dorsalis pedis artery are deep to the extensor

retinaculum ( both superior and inferior ) .

- a septum from the superficial part of IER separates the three

compartments :

1- tibialis anterior ( 1st compartment )

2- extensor hallucis longus ( 2nd compartment )

3- extensor digitorum longus ( 3rd compartment ) .

- synovial sheath is a cover structure that resembles bursa but surrounds the

entire tendon , and it has synovial membrane just like bursa and synovial

cavities in joints .

Lateral ( peroneal ) retinaculum :

- is a specialized retinaculum for peroneal muscles .

A- superior peroneal retinaculum (SPR) :from lateral malleolus to the

calcaneus , single band , peroneus brevis ( deep ) and peroneus longus (

superficial ) crosses the SPR side by side , so their tendons share the same

synovial sheath .

B- inferior peroneal retinaculum (IPR) : on lateral surface of the calcaneus ,

two bands , the tendons will move away from each other , so the synovial

sheath will divide .

Medial ( flexor ) retinaculum :

- passes from anterior surface of the calcaneus to the medial malleolus then

to the posterior surface of calcaneus .

- structures that passes beneath the flexor retinaculum :

( I ) most anterior ------> ( V ) most posterior :

I - synovial sheath of tibialis posterior

II - synovial sheath of flexor digitorum longus

III - posterior tibial artery

IV - tibial nerve

V - synovial sheath of flexor hallucis longus

- the tibial artery is the site of anesthesia of the sole .

Dorsalis pedis artery :

- it is a continuation of anterior tibial artery , superficial artery , deep to

extensor retinaculum ( the first structure beneath the ER ) .

- note that the tendons run within the ER not beneath it , so the artery is deep

to them and the ER but is superficial artery in the same time .

- after being superficial it runs inferior to the 1st tendon of extensor digitorum

brevis ( tendon of the hallucis belly ) , then penetrates the 1st dorsal

interosseous muscle and euns alongside with it , then at the plantar side joins

the plantar arch .

Muscles of the dorsum of foot :

- two muscles , innervated by deep fibular nerve ( L5 , S1 )

Muscles of the sole of foot : originate from calcaneus .

A- 1st layer ( superficial ) :

1- abductor hallucis muscle ( for big toe )

2- flexor digitorum brevis muscle "most superficial" ( for middle phalanges )

3- abductor digiti minimi muscle ( for 5th phalanx )

- deep peroneal nerve is lateral to dorsalis pedis artery .

B- 2nd layer :

1- quadratus plantae muscle : originate from the calcaneus , inserts on the

tendon of flexor digitorum longus ; flexor digitorum longus comes from the

posterior compartment , changes its path from lateral to medial side to enter

the sole , then inserts on the distal phalanges , it inserts on the tendon to

change the axis of the tendon ( oblique ) to match the axis of the sole (

straight ) .

2- lumbrical muscles : they are also connected to the tendon of the flexor

digitorum longus ( originated from it ) , they insert on the extensor expansion

with four tendons .

3- tendons of flexor digitorum longus

4- tendon of flexor hallucis longus

- tendons of all these muscles are on the same plane or level .

C- 3rd layer :

1- flexor hallucis brevis muscle : most medial , originate from the distal part of

tarsal bones , inserts on the base of the proximal phalanx of big toe ( inferior

border )

2- adductor hallucis muscle : intermediate , originate from the distal part of tarsal

bones , inserts on the base of the proximal phalanx of big toe ( lateral border ) ,

two heads ; transverse ( between heads of lateral metatarsals ) and oblique ( from

bases of metatarsals or cuneiforms ) .

3- flexor digiti minimi brevis muscle : most lateral , originate from the distal part of

tarsal bones , inserts on the inferior border of the base of 5th proximal phalanx .

D- 4th layer :

1- planter interossei muscles : adductors , three muscles ; 1st muscle with 3rd toe ,

2nd muscle with 4th toe , 3rd muscle with 5th toe . the big toe lacks interossei

because it is the hallucis and has its own muscles , and the 2nd toe lack interossei

because it is the axis ( in hand the 3rd finger is the axis ) .

2- dorsal interossei muscles : abductors , four muscles ; 1st (on medial side) and

2nd (on lateral side) muscles with 2nd toe , 3rd muscle with 3rd toe , 4th muscle

with 4th toe . the big toe and 5th toe lacks interossei because itthey have their

own separate abductor muscles .

- Medial planter artery : Smaller , Deep to abductor hallucis muscle .

- Lateral planter artery , Deep to the abductor hallucis muscle and flexor

digitorum brevis muscle , Continue as planter arch, and Planter digital artery .

- planter arteries and nerves ( medial and lateral ) are sandwiched between

the 1st and 2nd layers .

- planter arch is sandwiched between the 3rd and 4th layers .

- tibial nerve branches in the sole companies the medial and lateral planters .

- tendons of extensor digitorum muscle become superficial under extension

stress and can be easily located .

- dorsalis pedis artery is superficial to extensor hallucis and medial to the

deep peroneal nerve .

*actions and innervation of muscles are in the tables*

thank you and good luck