review of lower limb nerves/vessels Flashcards
innervation to lower limb
comes from lumbosacral plexus- femoral nerve supplies anterior thigh, obturator medial thigh, sciatic rest (posterior thigh, leg and foot)
anterior/posterior divisions
femoral supplies anterior thigh, but comes from POSTERIOR division (due to permanent torsion) obturator anterior, sciatic both posterior and anterior posterior= extensor muscles, anterior= flexor muscles
importance of piriformis
things emerging superior to piriformis are superior gluteal nerve/vessels inferior gluteal nerve/vessels and sciatic nerve are inferior, as well as posterior cutaneous nerve of thigh (largest cutaneous nerve)
importance of common peroneal nerve
goes around neck of fibula, so vulnerable to damage
saphenous nerve and sural nerve
major branch of femoral nerve- cutaneous for medial leg/foot, whereas sural cutaneous for lateral leg/foot
DIAGRAM from which roots do posterior cutaneous nerve emerge from
S1-2, as S1-2 supplies most region of posterior thigh AND leg
DIAGRAM autonomous sensory zones
confined zones where damage there is indicative of spinal root damage L3 is small region in anterior thigh, L4 is region in knee, S1 is region in posterior calf obturator nerve is medial thigh
DIAGRAM cutaneous innervation of foot with clinical significance
deep fibular (branch of common peroneal) supplies some toes- abnormal sensation there is indicative saphenous, sural and superficial fibular as well, with plantar nerves at base
prolapsed intervertebral disc at L5-S1 effects
motor- no eversion sensory- lateral edge of foot lost reflex- loss of ankle jerk (S1) minimal autonomic effects
what occurs with lesion at common peroneal nerve at fibular neck
motor- foot drop sensory- affects dorsum of foot no effect on reflexes/autonomic
effect of foot drop
leads to high stepping gait, and damage to sole due to pressure (aka TROPHIC DAMAGE- damage to surrounding tissue)
trifurcation of popliteal artery
anterior tibial artery (gives off dorsalis pedis artery) posterior tibial peroneal artery
only branch of internal iliac that goes into thigh
obturator artery
pulses in leg
femoral artery- press it against pubic ramus (between ASIS and pubic tubercle) popliteal artery, posterior tibial artery- behind medial malleolus (calcaneal tendon posterior) dorsalis pedis- press between 1st/2nd metatarsals, between EHL and tibialis anterior tendon
posterior tibial artery
goes behind medial malleolus
arteries of foot
lateral and medial plantar artery, and dorsalis pedis artery for dorsum
superficial veins+ pathway
great saphenous from dorsal venous arch- just anterior to medial malleolus, goes up medial leg/thigh, and joints to femoral vein at saphenous opening small saphenous from dorsal venous arch posterior to lateral malleolus- goes POSTERIORLY, and pierces fascia in popliteal fossa to joint popliteal vein
venae comitantes
not a single vein to accompany a single artery, but rather multiple veins- they are stuck to artery, so pulsations of artery promote venous flow also allows heat exchange
how to get fluid into body in leg, and what method preferred now
saphenous vein cut above medial malleolus- get fluid into body: occurs when venous cannulation not possible now put fluids in intraosseously (ie anterior tibia)
INTERMITTENT claudication vs acute limb ischaemia, cause, and muscle mainly affected
sudden occlusion = acute limb ischaemia GRADUAL occlusion= intermittent claudication (muscle pain upon exertion), usually due to ARTERIAL embolism affects calf usually
compartment syndrome
muscles separated by fascia- trauma increases pressure in a compartment (often in leg), which causes ischaemia by collapsing vessels (PULSES STILL felt) normal pressure (25mmhg) rises to 50-60
acute compartment syndrome vs chronic
often caused by trauma, where emergency fasciotomy needed (ie compartment opened up) to relieve pressure and prevent muscle death chronic due to exercise
important clinical point about lower limb veins- varicose veins,
superficial and deep veins connected by perforating veins eg sapheno-femoral junction- they have valves to ensure blood goes from superficial to deep if valve damaged, leads to swelling of superficial veins (VARICOSE veins), as well as venous ulcers and lipodermatosclerosis (thickening of skin)
how venous flow is supported, what occurs if not and treatment for it
many veins in distal leg between muscles- muscles contract to squeeze vein, and blood goes upwards to heart due to valves if not, leads to DVT- treated by elastic surgical sock (compress superficial veins)
