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
What are the ORIGINS of the FIBULARIS BREVIS?
The inferolateral surface of the fibular shaft
What are the ATTACHMENTS of the FIBULARIS BREVIS?
A tubercle on metatarsal V
What are the ACTIONS of the FIBULARIS BREVIS?
Eversion of the foot
What is the INNERVATION of the FIBULARIS BREVIS?
Superficial fibular (peroneal) nerve, L4-S1
How are the muscles in the posterior compartment of the leg organised?
into two layers superficial and deep, they are separated by a band of fascia
What are the muscles of the superficial section?
Gastrocnemius, plantaris and soleus
What are the muscles of the deep section?
Popliteus, tibialis posterior, flexor digitorum longus and flexor hallucis longus
What is the gastrocnemius?
The most superficial of all the muscles in the posterior leg. It has two heads - medial and lateral, which converge to form a single muscle belly
What are the ORIGINS of the GASTROCNEMIUS?
Lateral head - the lateral femoral condyle
Medial head - the medial femoral condyle
What are the ATTACHMENTS of the GASTROCNEMIUS?
The fibres of the two heads converge to form single belly which combines with the soleus to form the calcaneal tendon which inserts onto the calcaneus
What are the ACTIONS of the GASTROCNEMIUS?
It plantarflexes at the joint, and because it crosses the knee, it is a flexor at the knee
What is the INNERVATION of the GASTROCNEMIUS?
The tibial nerve
What is the plantaris?
A small muscle with a long tendon that descends down the leg. It is absent in 10% of people
What is the ORIGIN of the PLANTARIS?
The lateral supracondylar line of the femur
What are the ATTACHMENTS of the PLANTARIS?
The muscle descends medially and condenses into a tendon that blends with the calcaneal tendon
What are the ACTIONS of the PLANTARIS?
It plantarflexes the ankle joint, and because it crosses the knee, it is a flexor there.
It is not vital for these movements
What is the INNERVATION of the PLANTARIS?
The tibial nerve
What is the soleus?
A large, flat muscle located deep to the gastrocnemius
What are the ORIGINS of the SOLEUS?
The soleal line of the tibua and proximal fibular area
What are the ATTACHMENTS of the SOLEUS?
It joins the calcaneal tendon
What are the ACTIONS of the SOLEUS?
Plantarflexion of the foot at the ankle joint
What is the INNERVATION of the SOLEUS?
The tibial nerve
What is the popliteus?
a muscle located superiorly in the leg behind the knee joint
What are the ORIGINS of the POPLITEUS?
the lateral condyle of the femur and the posterior horn of the lateral meniscus
What are the ATTACHMENTS of the POPLITEUS?
Above the origin of the soleus muscle
What are the ACTIONS of the POPLITEUS?
Laterally rotates the femur on the tibia - ‘unlocking’ the knee joint so that flexion can occur
What is the INNERVATION of the POPLITEAL?
The tibial nerve
What is the tibialis posterior?
The deepest of the four deep muscles. It lies between the flexor digitorum longus and the flexor hallucis longus
What are the ORIGINS of the TIBIALIS POSTERIOR?
The interosseous membrane between the tibia and fibula, and posterior surfaces of the two bones
What are the ATTACHMENTS of the TIBIALIS POSTERIOR?
The plantar surfaces of the medial tarsal bones
What are the ACTIONS of the TIBIALIS POSTERIOR?
Inverts and plantarflexes the foot, maintains the medial arch of the foot
What is the INNERVATION of the TIBIALIS POSTERIOR?
The tibial nerve
What is the flexor digitorum longus?
A smaller muscle than the flexor hallucis longus, located ,edially in the posterior leg
What are ORIGINS of the FLEXOR DIGITORUM LONGUS?
The medial surface of the tibia
What are the ATTACHMENTS of the FLEXOR DIGITORUM LONGUS?
The plantar surface of the of the lateral four digits
What are the ACTIONS of the FLEXOR DIGITORUM LONGUS?
Flexes the lateral four toes
What is the INNERVATION of the FLEXOR DIGITORUM LONGUS?
The tibial nerve
What is the flexor hallucis longus?
A muscle found on the lateral side of the leg (opposite the big toe which is what it acts on)
What are the ORIGINS of the FLEXOR HALLUCIS LONGUS?
The posterior surface of the fibula
What are the ATTACHMENTS of the FLEXOR HALLUCIS LONGUS?
The plantar surface of the phalanx of the big toe
What are the ACTIONS OF THE FLEXOR HALLUCIS LONGUS?
Flexion of the big toe
What is the INNERVATION of the FLEXOR HALLUCIS LONGUS?
Tibial nerve
What are the two groups of muscles acting on the foot?
Extrinsic and intrinsic
What are the extrinsic muscles of the foot?
Muscles that arise from the leg and act on the foot
What are the intrinsic muscles of the foot divided into?
Dorsal and plantar
What are the dorsal intrinsic muscles of the foot?
extensor digitorum brevis, and the extensor hallucis brevis
What is the Extensor Digitorum Brevis?
A muscle that lies deep to the tendon of the extensor digitorum longus