Muscles of the Leg Flashcards
Which of the adductors has the longest origin?
Adductor magnus
What is the extent of adductor magnus’ origin?
From inferior pubic ramus to ischial ramus
Why is the last part of adductor magnus called the hamstrings part?
Has origin very close to hamstrings
Implications for nerve supply
What is the anatomical definition of the leg?
Between knee and ankle
Does the leg have a fascia?
Yes
Thick
Continuous with tensor fascia lata of thigh
Where is the deep fascia of the leg?
Encircles tibia and fibula, and all muscles
Where is the posterior compartment of the leg?
Behind
- Interosseus membrane
- Tibia
- Fibula
- Posterior intermuscular septum
Where is the anterior compartment of the leg?
In front of
- Tibia
- Interosseus membrane
- Fibula
- Anterior intermuscular septum
Where is the lateral compartment of the leg?
Between fibula and exterior of deep fascia
How many planes of muscle does each compartment of the leg have?
Anterior and lateral = 1
Posterior = 2
- Superficial
- Deep
What do the muscles in the anterior compartment of the leg do?
Dorsi-flex foot
Extend toes
What do the muscles in the posterior compartment of the leg do?
Plantar-flex foot
Flex toes
What do the muscles in the lateral compartment of the leg do?
Evert foot
How is the deep fascia of the leg tethered to the fibula?
Via anterior and posterior intermuscular septum
How is the deep fascia of the leg tethered to the tibia?
Adheres directly to subcutaneous surface
Where is the interosseus membrane in the leg?
Between tibia and fibula
How many muscles are there in the anterior compartment of the leg?
3
How many muscles are there in the lateral compartment of the leg?
2
What are the muscles of the anterior compartment of the leg?
Tibialis anterior
Extensor hallicus longus
Extensor digitorum longus
From where do all the muscles of the anterior compartment of the leg arise?
Anterior aspects of shafts of tibia and fibula
What is the neurovascular supply of the anterior compartment of the leg?
Deep fibular nerve
Anterior tibial vessels
What does tibialis anterior do?
Dorsiflexor and inverter of foot
Where does tibialis anterior go?
Medial aspect of foot
What is the origin of tibialis anterior?
Anterior aspect of shaft of tibia and interosseus membrane
What is the distal attachment of tibialis anterior?
Medial cuneiform and base of 1st metatarsal
What does extensor hallicus longus do?
Dorsiflexor/extensor of great toe
What is the insertion of extensor hallicus longus?
Base of distal phalanx of great toe
What action does extensor hallicus longus have over all the joints it passes over?
Extends them
- Ankle
- Joints of foot
- Interphalangeal joint of great toe
What does extensor digitorum longus do?
Dorsiflexor/extensor of toes 2-5
What is the origin of extensor digitorum longus?
Anterior aspect of shaft of fibula and interosseus membrane
What happens to the tendon of extensor digitorum longus on the lateral toes?
Broadens into dorsal expansion - 1 for each toe
What are the insertions of extensor digitorum longus?
Central part of each tendon goes into base of 2nd phalanx
Lateral parts of each tendon go into base of distal phalanx
What is fibularis tertius?
Small part of extensor digitorum longus
Shares same belly
Has separate tendon that splits off
What is the attachment of fibularis tertius?
Base of 5th metatarsal
Does fibularis tertius extend the toes?
No
Where is extensor digitorum brevis?
On dorsum of foot
Extensions going to each of toes
During flexion of the ankle, what holds the tendons in place and stops them from bowstringing?
Extensor retinaculum
Describe the two bands of the extensor retinaculum
Superior band = thickening in deep fascia
- Proximal to ankle
Inferior band = Y shaped
- Upper part of Y extends across medial malleolus > blends into deep fascia of sole of foot
- Lower part of Y attaches to lateral aspect of calcaneus
What is the deep fascia of the sole of the foot called?
Plantar fascia
What is the mnemonic for remembering the arrangement of structures running underneath the extensor retinaculum and onto the dorsum of the foot, from medial to lateral?
Timothy has a nasty, dirty toe
What does “Timothy has a nasty, dirty toe” stand for?
Timothy = tibialis anterior Has = extensor hallicus longus A = anterior tibial artery and veins Nasty = deep fibular nerve Dirty = Extensor digitorum longus Toe = fibularis tertius
What are the muscles of the lateral compartment of the leg?
Fibularis longus
Fibularis brevis
What do fibularis longus and brevis do?
Evert foot
What is the origin of fibularis longus and brevis?
Lateral fibula
Compare the origins and insertions of fibularis longus and brevis
Fibularis longus has more proximal origin and distal insertion than fibularis brevis
Which fibularis muscle is deep to which?
Fibularis brevis deep to fibularis longus
What is the relationship between the tendons of fibularis longus and brevis and the lateral malleolus?
Both pass behind
Fibularis brevis grooves bone as it passes directly behind
What is the insertion of fibularis brevis?
Base of 5th metatarsal
How does fibularis longus get to its insertion?
Passes onto sole of foot
Grooves cuboid bone along the way
Goes right over to medial side of foot
What is the insertion of fibularis longus?
Base of 1st metatarsal and medial cuneiform
With which muscle does fibularis longus share its insertion?
Tibialis anterior
What is the nerve supply of the lateral compartment of the leg?
Superficial fibular nerve
What is the retinaculum of the lateral compartment of the leg?
Fibular retinaculum
Where does the fibular retinaculum hold the tendons of the lateral compartment in place?
2 parts, as they pass behind lateral malleolus
What is the extent of the superior part of the fibular retinaculum?
From lateral malleolus
To lateral calcaneus
What is the extent of the inferior part of the fibular retinaculum?
Continuous with inferior part of extensor retinaculum as it goes onto lateral part of calcaneus
What is the arrangement of the tendons of the lateral compartment of the leg as they pass under the inferior part of the fibular retinaculum?
Superior = fibularis brevis Inferior = fibularis longus
What is the neurovascular supply of the posterior compartment of the leg?
Innervated by tibial nerve
Supplied by posterior tibial vessels
What are the superficial muscles of the posterior compartment of the leg?
Gastrocnemeus
Soleus
Plantaris
Describe the bellies of gastrocnemius
2 fleshy bellies 1 from each of condyles of femur Medial head from medial condyle Lateral head from lateral condyle Forms bulk of calf
Where do all the superficial muscles of the posterior compartment of the leg converge?
On thick tendon at back of heel = tendocalcaneus
Where does tendocalcaneus go onto?
Posterior surface of calcaneus
What is tendocalcaneus also known as?
Achilles’ tendon
Where do the tendons of the deep muscles of the posterior compartment of the leg go?
Onto sole of foot
What do the tendons of the deep muscles of the posterior compartment of the leg do on the sole of the foot?
Flex toes
What is happening to plantaris phylogenetically?
Degenerating from species
What is the origin of plantaris?
Edge to edge with lateral belly of gastrocnemius, just above it
What is the course of plantaris?
Runs underneath medial head of gastrocnemius
What is the insertion of plantaris?
Long slender tendon blends with medial aspect of tendocalcaneus
In which compartment is popliteus?
Posterior compartment of leg
What is the shape of popliteus?
Thing
Triangular
What is popliteus’ relationship to the popliteal fossa?
Forms inferior part of floor
What is the popliteal fossa?
Diamond shaped region at back of knee
What forms the bony part above the popliteal fossa?
Popliteal surface of femur
What’s in the middle of the popliteal fossa?
Ligamentous/capsular part directly behind knee joint
What is the proximal attachment of popliteus?
Lateral aspect of lateral femoral condyle and lateral meniscus
What is the distal attachment of popliteus?
Tibia above soleal line
What is popliteus’ signficance as a flexor?
Insignificant
What does popliteus do?
Important role in unlocking knee
What is between the two attachments of the origin of soleus?
Fibrous arch
Where does the neurovascular bundle for the posterior compartment go once it comes through the popliteal fossa?
Goes under fibrous arch of soleus
Describe the origin of soleus
Horseshoe shaped, spanning tibia and fibula
Linear origin edge to edge with inferior margin of popliteus
What vascular structure is deep to soleus?
Complex venous plexus
Muscular action of soleus pushes blood back up to heart = calf muscle pump
What are the deep muscles of the posterior compartment of the leg?
Flexor digitorum longus
tibialis posterior
Flexor hallicus longus
Which muscle is in the centre of the deep part of the posterior compartment of the leg?
Tibialis posterior
Which muscle is medial in the deep part of the posterior compartment of the leg?
Flexor digitorum longus
Which muscle is lateral in the deep part of the posterior compartment of the leg?
Flexor hallicus longus
What does tibialis posterior do?
Plantar-flexor
What happens when tibialis anterior and posterior contract together?
Invert foot
Where do the deep posterior compartment muscles of the leg go as they reach the foot?
Pass behind medial malleolus
Onto sole of foot
What stops the deep muscles of the posterior compartment of the leg from bowstringing at the ankle?
Flexor retinaculum
What is the extent of the flexor retinaculum?
From medial malleolus down to side of calcaneus
Where does flexor hallicus longus go after passing under the flexor retinaculum?
Heads towards great toes
Crosses under flexor digitorum longus
What is the insertion of tibialis posterior?
Medial cuneiform and base of 5th metatarsal
Where does flexor digitorum longus go after passing under the flexor retinaculum?
Heads onto toes 2-5
Crosses over flexor hallicus longus
What is the mnemonic to remember the order of structures passing under the flexor retinaculum?
Tom, Dick, and very naughty Harry
What does “Tom, Dick, and very naughty Harry” stand for?
Tom = tibialis posterior Dick = flexor digitorum longus And = Posterior tibial artery Very = posterior tibial veins Naughty = tibial nerve Harry = flexor hallicus longus