Muscles of the lower leg Flashcards
What muscles are part of the anterior compartment of the leg?
The tibialis anterior, extensor digitorum longus, extensor hallucis longus and fibularis tertius
What is the collective action of the muscles in the anterior compartment of the leg?
Dorsiflexion and inversion of the foot at the ankle joint
What is the tibialis anterior?
It is located alongside the lateral surface of the tibia and is the strongest dorsiflexor of the foot.
To test the power of the tibialis anterior, the patient can be asked to stand on their heels.
What are the ORIGINS of the TIBIALIS ANTERIOR?
The lateral surface of the tibia
What are the ATTACHMENTS of the TIBIALIS ANTERIOR?
the medial cuneiform and the base of metatarsal I.
What are the ACTIONS of the TIBIALIS ANTERIOR?
Dorsiflexion and inversion of the foot
What is the INNERVATION of the TIBIALIS ANTERIOR?
The deep fibular nerve
What is the extensor digitorum longus?
Lies lateral and deep to the tibialis anterior. The tendons can be palpated on the dorsal surface of the foot
What are the ORIGINS of the DIGITORUM LONGUS?
The lateral condyle of the tibia and the medial surface of the fibula
What are the ATTACHMENTS of the DIGITORUM LONGUS?
The fibres of the muscle converge into a tendon which travels to the dorsal surface of the foot. It then splits into 4 each inserting onto a toe
What are the ACTIONS of the DIGITORUM LONGUS?
Extension of the lateral four toes and dorsiflexion of the foot
What is the INNERVATION of the DIGITORUM LONGUS?
Deep fibular nerve
Where is the extensor hallucis longus?
It is located deep to the EDL and TA
What are the ORIGINS of the EXTENSOR HALLUCIS LONGUS?
The medial surface of the fibular shaft
what are the ATTACHMENTS of the EXTENSOR HALLUCIS LONGUS?
The tendon crosses anterior to the ankle joint and attaches to the base of the distal phalanx of the big toe
What are the ACTIONS of the EXTENSOR HALLUCIS LONGUS?
Extension of the big toe and dorsiflexion of the foot
What is the INNERVATION of the EXTENSOR HALLUCIS LONGUS?
The deep fibular nerve
What is the fibularis tertius?
A muscle that arises from the most inferior part of the extensor digitorum longus. It is not present in all individuals
What are the ORIGINS of the FIBULARIS TERTIUS?
With the extensor digitorum longus from the medial surface of the fibula
What are the ATTACHMENTS of the FIBULARIS TERTIUS?
The tendon descends with the extensor digitorum longus, until they reach the dorsal surface of the foot where the fibularis tertius tendon diverges and attaches to metatarsal V
What are the ACTIONS of the FIBULARIS TERTIUS?
Eversion and dorsiflexion of the foot
What is the INNERVATION of the FIBULARIS TERTIUS?
The deep fibular nerve
What are the muscles in the lateral compartment of the leg?
Fibularis longus and brevis
What is the common function of the lateral compartment of the leg?
Eversion (turning the sole of the foot outwards)
What is the fibularis longus?
It is the larger and more superficial muscle in the lateral compartment
What are the ORIGINS of the FIBULARIS LONGUS?
The superior and lateral surface of the fibula and the lateral tibial condyle
What are the ATTACHMENTS of the FIBULARIS LONGUS?
The fibres of the muscle converge into a tendon and descend into the foot then attach to the bones on the medial side of the foot namely the medial cuneiform and base of metatarsal I.
What are the ACTIONS of the FIBULARIS LONGUS?
Eversion and plantarflexion of the foot. Also supports the lateral and transverse arches of the foot
What is the INNERVATION of the FIBULARIS LONGUS?
Superficial fibular (peroneal) nerve, L4-S1
What is the fibularis brevis?
A deeper and shorter muscle than the fibularis longus