Anatomy - Muscles Of Leg Flashcards
Anterior muscles of the leg
Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus
Innervation of the anterior muscles of the leg
Deep peroneal/ fibular nerve
Tibialis anterior
Closest muscle to tibia & crosses the ankle anteriorly to attach to the medial aspect of foot
Adjacent to subcutaneous border of tibia
Involved in ankle extension (dorsiflexion) and ankle inversion - also requires Tibialis posterior
Extensor digitorum longus
Splits into 4 tendons - one to each 4 lateral digits
Involved in extension of digits and ankle joint
Extensor hallucis longus
Tendon attaches to big toe
Lies between tibialis anterior and extensor digitorum
Involved in extension of great toe
‘Foot drop’
Usually occurs if deep peroneal nerve becomes compromised
Can’t clear the floor when walking (inability to extend ankle joint)
Signs of ‘foot drop’
Scuff marks on the front of shoes
High stepping gait
How is the deep peroneal nerve usually compromised
Compression at neck of fibula
Function of fibularis muscles
Ankle eversion
Innervation of fibularis muscles
Superficial branch of common fibular/peroneal nerve
Fibularis longus
Passes laterally under LM to attach to medial aspect of the foot
Superficial to brevis
Supports transverse arch
Fibularis brevis
Passes laterally under LM to attach to lateral aspect of foot
Deep to longus
Posterior muscles of the leg
Gastrocnemius Soleus Plantaris Flexor digitorum longus Flexor hallucis longus Tibialis posterior
What is the popliteal fossa bound by
Hamstring muscles - superiorly
Gastrocnemius - inferiorly
Contents of the popliteal fossa
Popliteal artery Popliteal vein Terminal branch of sciatic nerve Tibial nerve Common peroneal nerve
Gastrocnemius
Has 2 heads that attach proximally to the posterior aspect of the femoral condyles and attaches distally at the calcaneous
Crosses the knee and ankle posterioly
Actions at the gastrocnemius
Crosses knee and ankle posteriorly - knee flexion and ankle flexion (plantarflexion)
Soleus
Attaches to tibia + fibula and blends w/ gastrocnemius tendon to attach to calcaneus (Achilles’ tendon)
Plantaris
V. thin tendon that blends w/ Achilles’ tendon
Superficial compartment of the posterior compartment of the leg
Gastrocnemius
Soleus
Plantaris
Deeper compartment of the posterior compartment of the leg
Flexor digitorum longus
Flexor hallucis longus
Tibialis posterior
Tibialis posterior
Supports spring ligament and medial longitudinal arch of foot
Allows plantar flexion and ankle inversion
Innervation of posterior muscles of the leg
Tibial nerve
Sural nerve
Cutaneous branch of tibial nerve
Soleal pump
Helps venous blood return to heart
Superficial venous system
Great saphenous vein
Short saphenous vein
Great saphenous vein
Drains into femoral nerve
Short saphenous vein
Runs into popliteal vein and drains into popliteal fossa
Deep venous system
Runs alongside the arteries
Venae commitantes
When muscles in the leg contract (calf muscle pump), blood is pushed up
Venae commitantes
Run either side of posterior tibial artery
Why is the leg encased in deep fascia
Compartmentalizes muscle
Provides external support
Increases force on veins when contracting, acts as a restraining envelope
When does compartment syndrome occur
When pressure within compartment > pressure in capillaries
Capillaries can’t fill and supply blood to structures within the comportment ——-> ischaemia ——> avascular necrosis
When are varicosities seen
When the valves fail
Simmonds-Thompson test
Squeezing each calf when patient is lying face down on bed w/ legs dangling off of bed
Should cause muscles to contract ——> plantar flexion of the ankle joint
Treatment of a ruptured Achilles’ tendon
Surgically repaired
Wear a ‘moon boot’ during recovery- allows affected muscles to be in a position of non-function. Avoids stretching muscle —-> rupture heals faster
Lateral leg muscles
Ankle evertors
Peroneus longus
Peroneus brevis
Peroneus tertius
Peroneus tertius
Small muscle branching from extensor digitorum
Attaches to lateral aspect of foot
Flexor digitorum longus
Proximally, attaches to tibia
Runs behind MM and splits into 4 tendons - one for each digit
Flexor hallucis longus
Proximally, attaches to fibula
Passes medially to the hallux