Lower Limb III: Knee & Leg

knee joint: actions + articulation

• some rotation, flexion, and extension

• primary articulation between the condyles of the femur and tibia

anterior cruciate ligament: function

prevent hyperextension of the knee and limits anterior displacement of the tibia on the femur

posterior cruciate ligament: function

prevents hyperflexion of the knee and posterior displacement of the tibia on the femur

if the knee is hit by a blow from the lateral side when the foot is anchored, what structures can tear?

tibial collateral ligament, medial meniscus, anterior cruciate ligament

test for medial collateral ligament

• valgus stress test

• varus stress test

• anterior drawer test

• lachman test

• posterior drawer test

• McMurrary Test

valgus stress test

test for lateral collateral ligament

• valgus stress test

• varus stress test

• anterior drawer test

• lachman test

• posterior drawer test

• McMurrary Test

varus stress test

test for anterior cruciate ligament

• valgus stress test

• varus stress test

• anterior drawer test

• lachman test

• posterior drawer test

• McMurrary Test

anterior drawer test and lachman test

test for posterior cruciate ligament

• valgus stress test

• varus stress test

• anterior drawer test

• lachman test

• posterior drawer test

• McMurrary Test

posterior drawer test

test for menisci

• valgus stress test

• varus stress test

• anterior drawer test

• lachman test

• posterior drawer test

• McMurrary Test

McMurray Test

popliteal fossa: boundaries

biceps femoris muscle, semimembranous muscle, semitendinous muscle, heads of the gastrocnemius muscle

vasculature within the popliteal fossa

small saphenous vein, popliteal artery, popliteal vein, tibial nerve, common fibular nerve

divisions of the popliteal artery

anterior tibial artery and posterior tibial artery (branches into fibular artery)

where do each of the popliteal artery branches go: anterior and posterior tibial artery, fibular artery

• anterior tibial artery: anterior compartment

• posterior tibial artery: posterior compartment

• fibular artery: lateral compartment

what does the common fibular nerve divide into? Where do each innervate?

superficial fibular nerve (lateral) and deep fibular nerve (anterior)

anterior compartment of the leg: primary actions, innervation, and blood supply

• dorsiflex, extend toe, invert foot

• deep fibular nerve

• anterior tibial artery

lateral compartment of the leg: primary actions, innervation, blood supply

• evert foot

• superficial fibular nerve

• perforating branches of the fibular artery

posterior compartment of the leg: primary actions, innervation, blood supply

• planterflex, flex toes, invert foot

• tibial nerve

• posterior tibial artery

what are the 3 principle muscles of the anterior compartment of the leg? (hint: tom, dick. harry)

tibialis anterior, extensor hallucis longus, extensor digitorum longus

what muscle in the anterior compartment of the leg dorsiflexes the ankle and inverts the foot?

tibialis anterior

extensor hallucis longus: actions

extends big toe and dorsiflexes ankle

this muscle in the anterior compartment of the leg extends toes 2-5 and dorsiflexes the ankle

extensor digitorum longus

2 muscles of the lateral compartment of the leg

fibularis longus and fibularis brevis

this muscle passes across the sole of the foot and helps maintain one of the arches of the foot (under extreme loads)

fibularis longus

fibularis longus and brevis: actions, innervation, blood supply

• evert the foot

• innervated by the superficial fibular nerve

• supplied by branches of the fibular artery

what are the superficial muscles in the superior compartment of the leg? (hint: GPS) what do they all do?

gastrocnemius, soleus, plantaris; all plantarflexes the ankle

which muscles plantarflexes the ankle and flexes the leg?

gastrocnemius and plantaris muscles

this muscle medially rotates the tibia on the femur to unlock the knee at onset of flexion

popliteus muscle

tibialis posterior: actions

plantarflexes ankle and inverts the foot

flexor hallucis longus: actions

flexes big toe and plantarflexes the ankle

this muscle flexes toes 2-5 and plantarflexes the ankle

flexor digitorum longus