MSK Muscles of the leg Flashcards
Name the muscles in the anterior compartment of the leg
Tibialis anterior
Fibularis tertius
Extensor digitorum longus
Extensor hallucis longus
What are the attachments and actions of the tibialis anterior?
Located on lateral surface of tibia
Originates from lateral tibia and attaches to medial cuneiform and base of metatarsal 1
Actions:
Strongest dorsiflexor of foot
Inverts foot
How would you test the power of tibialis anterior?
Ask the patient to stand on their heels
What are the attachments and actions of the extensor digitorum longus?
Lateral and deep to tibialis anterior
Originates from lateral condyle of tibia and medial surface of fibula, fibres converge to a tendon which inserts onto each of the 4 toes
Actions:
Extension of lateral 4 toes
Dorsiflexion of foot
What are the attachments and actions of the extensor hallucis longus?
Located deep to tibialis anterior and extensor digitorum longus
Originates from medial surface of fibular shaft and tendon crosses anterior to ankle joint and attaches to base of distal phalanx of great toe
Actions:
Extension of great toe
dorsiflexion
What are the attachments and actions of the fibularis tertius?
Not present in all individuals
Originates from the most inferior part of the extensor digitorum longus, the tendon descends with the EDL until the foot where the tendon diverges to attach to metatarsal 5
Actions:
Eversion and dorsiflexion
What is is innervation and blood supply to the anterior leg muscles?
Deep fibular nerve (L4-5)
Anterior tibial artery
What is the clinical sign of damage to the deep fibular nerve?
Footdrop due to paralysis of the anterior leg muscles
There is unopposed pull of the plantarflexor muscles producing permanent plantarflexion
The patient will have difficulty walking so to overcome this they will do the ‘eversion flick’, flicking the affected foot out whilst walking
Name the muscles in the lateral compartment of the leg
Fibularis longus and brevis
What are the attachments and actions of the fibularis longus?
Most superficial of the two
Originates from lateral and superior surface of fibula and lateral tibial condyle. The fibres converge into a tendon which enters foot posterior to lateral malleolus. Tendon crosses under the foot and attaches to medial cuneiform and base of metatarsal 1 on medial side
Actions:
Eversion and plantarflexion
Supports arches of the foot
What are the attachments and actions of the fibularis brevis?
Deeper than fibularis longus
Originates from inferior and lateral surface of fibular shaft, descends with the fibularis longus tendon and travels into foot posterior to lateral malleolus. Attaches to metatarsal 5
Actions:
Eversion of foot
What is the innervation of the lateral muscles of the leg?
Superficial fibular nerve (L4-S1)
How can you locate the superficial fibular nerve during dissection?
Use the fibularis longus as a landmark
There is a gap between the parts of the fibularis longus that originate from fibular head and neck - the common fibular nerve passes through this gap then bifurcates into deep and superficial branches
Name the superficial and deep muscles in the posterior compartment of the leg
Superficial muscles:
Gastrocnemius
Plantaris
Soleus
Deep muscles: Popliteus Tibialis posterior Flexor digitorum longus Flexor hallucis longus
Where do the superficial muscles of the posterior region of the leg insert?
They insert into the calcaneus of the foot via the calcaneal tendon
What are the bursae in the calcaneal tendon?
Subcutaneous calcaneal bursa - between skin and calcaneal tendon
Deep bursa of the calcaneal tendon - between tendon and calcaneus
Superficial
What are the attachments and actions of the gastrocnemius?
Most superficial, comprises mainly of fast twitching muscle fibres which produce forceful movements such as running and jumping
Lateral + medial head originate from lateral +medial femoral condyle. The muscle belly combines with soleus and inserts into calcaneus
Actions:
flexes knee
plantarflexion
Superficial
What are the attachments and actions of the plantaris?
Small muscle with long tendon
Originates from lateral supracondylar line of femur and descends medially between gastrocnemius and soleus.
Actions:
flexes knee
plantarflexion
Superficial
What are the attachments and actions of the soleus?
Deep to gastrocnemius, large and flat like a sole fish
Originates from soleal line of tibia and proximal fibular, narrows in the lower leg and joins the calcaneal tendon
Actions:
plantarflexion
What is the innervation of the posterior compartment of the leg?
Tibial nerve
How does the calcaneal tendon get ruptured and what is the treatment?
Caused by forceful plantarflexion
The affected foot will be permanently dorsiflexed
Treatment is usually non-surgical
What are the attachments and actions of the popliteus?
Forms base of the popliteal fossa
There is a popliteal bursa between the popliteal tendon and the posterior surface of knee joint
Originates from posterior surface of proximal tibia and fibres pass up to the lateral condyle of femur
Actions:
Laterally rotates femur which unlocks the knee so flexion can occur
What are the attachments and actions of the tibialis posterior?
Deepest of the 4 deep posterior
Originates from interosseous membrane and posterior surfaces of tib and fib, enters the foot posterior to medial malleolus and attaches to plantar surfaces of medial tarsal bones.
Actions:
Inverts and plantarflexes foot
Maintains the medial arch
What are the attachments and actions of the flexor digitorum longus?
Smaller than flexor hallucis longus, located medially
originates from medial surface of tibia and attaches to plantar surface of lateral 4 digits
Actions:
flexes lateral 4 toes
What are the attachments and actions of the flexor hallucis longus?
Located laterally
Originates from posterior surface of fibula and attaches to plantar surface of the phalanx of the great toe
Actions:
flexes the great toe
