Muscles in the Anterior Compartment of the Leg Flashcards
How many muscles are there in the anterior compartment of the leg?
4
What are the muscles in the anterior compartment of the leg?
Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus
Fibularis tertius
What do the muscles of the anterior compartment of the leg collectively act to do?
Dorsiflex and invert the foot at the ankle joint
What muscles extend the toes?
The extensor digitorum longus and extensor hallucis longus
What are all the muscles in the anterior compartment of the leg innervated by?
The deep fibular nerve (L4-L5)
What is the arterial supply of all the muscles in the anterior compartment of the leg?
The anterior tibial artery
Where is the tibialis anterior muscle located?
Alongside the lateral surface of the tibia
How is the action of the tibialis anterior tested?
The patient can be asked to stand on their heels
What is the proximal attachment of the tibialis anterior?
Lateral condyle and superior half of lateral surface of tibia and interosseous membrane
What is the distal attachment of the tibialis anterior?
Medial and inferior surfaces of medial cuneiform and base of 1st metacarpal
What is the main action of the tibialis anterior?
Dorsiflexes ankle
Inverts foot
Where does the extensor digitorum longus lie?
Lateral and deep to the tibialis anterior
Where can the tendons of the extensor digitorum longus be palpated?
On the dorsal surface of the foot
What is the proximal attachment of the extensor digitorum longus?
Lateral condyle of the tibia and superior three quarters of the medial surface of the fibula and interosseous membrane
What is the distal attachment of the extensor digitorum longus?
Middle and distal phalanges of lateral four digits
What is the main action of the extensor digitorum longus?
Extends lateral four digits
Dorsiflexes ankle
Where is the extensor hallicus longus located?
Deep to the EDL and TA
What is the proximal attachment of the extensor hallucis longus?
Middle part of anterior surface of fibula and interosseous membrane
What is the distal attachment of the extensor hallucis longus?
Dorsal aspect of base of distal phalanx of great toe (hallux)
What is the main action of the extensor hallucis longus?
Extends great toe
Dorsiflexes ankle
Where does the fibularis tertius muscle arise from?
The most inferior part of the EDL
Is the fibularis testis present in all individuals?
Yes
What is the proximal attachment of the fibularis tertius?
Inferior third of anterior surface of fibula and interosseous membrane
What is the distal attachment of the fibularis tertius?
Dorsum of base of 5th metatarsal
What is the main action of the fibularis tertius?
Dorsiflexes ankle
Aids in eversion of foot
What is footdrop?
A clinical sign indicating paralysis of the muscles in the anterior compartment of the leg
When is footdrop most commonly seen?
When the common fibular nerve is damaged
What arises from the common fibular nerve?
The deep fibular nerve
What happens in footdrop?
The muscles in the anterior compartment are paralysed, and so the unopposed pull of the plantarflexor muscles (found in the posterior leg) produces pernament plantarflexion
What can footdrop interfere with?
Walking
Why can footdrop interfere with walking?
The affected limb can drag along the ground
How can dragging of the foot with footdrop be circumvented?
The patient can flick the foot outwards while walking, known as an ‘eversion flick’.
