lower limb nerves Flashcards
lumbar plexus nerves (Interested In Getting Laid On Fridays)
Iliohypogastric L1
Ilioinguinal L1
Genitofemoral L1 L2
Lateral femoral cutaneous L2 L3
Obturator L2 L3 L4
Femoral L2 L3 L4
tendon tests for nerve roots
patellar/quadriceps reflex: L2, L3, L4
ankle jerk reflex (Achilles tendon): S1, S2
sciatic nerve supply
L4-S3, supplies the posterior compartment of the thigh, divides into tibial and fibular nerves
tibial nerve supply
S1-S2, passes through soleus to supply posterior leg muscles, then passes behind medial malleolus to split into medial and lateral plantar nerves
fibular nerve supply
L4-S3, gives off lateral cutaneous nerve of calf at posterior fossa, passes behind head of fibula, supplies anterior and lateral leg, divides into superficial and deep peroneal nerves
obturator nerve supply
L2-L4, runs through obturator canal to supply medial compartment of thigh, enters and leaves adductor canal through the adductor hiatus to supply knee joint
femoral nerve supply
L2-L4, passes between the iliacus and psoas to run through the femoral triangle and supply the anterior compartment of the thigh (+cutaneous supply of medial and anterior thigh), branches to form saphenous nerve
saphenous nerve supply
L3-L4, runs down medial side of leg with great saphenous vein to supply medial leg, passes in front of medial malleolus to supply skin of medial border of foot up to big toe
medial plantar nerves supply
runs with medial plantar artery to supply medial 3.5 toes, 1st lumbrical, abductor hallucis, flexor digitorum brevis
lateral plantar nerve supply
runs with lateral plantar artery to supply lateral 1.5 toes, lumbricals 2-4, abductor digiti minimi, all interossei
superficial peroneal nerve supply
lateral leg muscles, skin of anterolateral leg surface and dorsum of foot
deep peroneal nerve supply
pierces the anterior septum to supply anterior leg muscles, lies lateral to anterior tibial artery, enters dorsum of foot lateral to dorsalis pedis artery
sciatic nerve lesions presentation
sensory loss: mostly below knee, decreased sensation and numbness, tingling and burning sensation
motor loss: weak extension of hip and flexion of knee, gait abnormal, foot drop
autonomic loss: dry, hot, red
what does dry hot red autonomic loss of nerve supply mean
flushed skin due to lack of vasoconstriction, hair unable to stand due to paralysed erector pilli
fibular nerve lesions presentation
sensory loss: on skin of leg and foot anteriorly and laterally
motor loss: weak ankle extension, flexion, inversion, foot drop due to unopposed posterior leg flexor muscles
autonomic loss: dry, hot, red
femoral nerve lesions presentations (rare though)
sensory loss: anterior and medial thigh, medial leg down to big toe
motor loss: loss of knee flexion
autonomic loss: dry, hot, red
tibial nerve lesions presentation (rare bc nerve runs deep)
sensory loss: sole of foot
motor loss: posterior leg muscles and plantar flexion, opposing muscles dorsiflex and evert foot
autonomic loss: dry, hot, red
lower limb dermatomes
L1: inguinal region
L2: lateral thigh
L3: medial thigh
L4: medial leg
L5: dorsum of foot
S1: heel to knee
S2: lateral leg and posterior thigh
S3+S4: gluteal region
femoral artery branches (perform extreme cramming, pathetic profs)
Profunda femoris (branches to lateral and medial circumflex femoral arteries)
superficial Epigastric artery
superficial Circumflex iliac artery
superficial external Pudendal artery
deep external Pudendal artery
femoral artery supply
anterior and anteromedial aspects of thigh
profunda femoris supply
medial, posterior and lateral part of thigh
obturator artery supply
anterior and posterior branches encircle the obturator foramen, supplies the head of the femur
anterior tibial artery supply
becomes the dorsalis pedis at the ankle
supplies the anterior compartment of the leg and dorsum of the foot
posterior tibial artery supply
branch of the popliteal artery, branches into peroneal, medial and plantar arteries, supplies the posterior compartment of the leg and sole of the foot
arterial supply to the foot
plantar artery (branch of posterior tibial artery) gives branches supplying each toe
dorsalis pedis (branch of anterior tibial artery) supplies the foot
how to calculate ankle brachial index
arm blood pressure over ankle blood pressure
(if <1: narrow ankle blood vessels and claudication)
venous drainage of the great saphenous vein
dorsal digital vein of big toe + dorsal venous arch –> ascends to the medial malleolus of the tibia –> receives the superficial circumflex iliac vein + superficial epigastric vein + superficial external pudendal vein at the tensor fascia lata –> drains into femoral vein
venous drainage of small saphenous vein
dorsal digital vein of 5th toe + dorsal venous arch –> ascends posterior to lateral malleolus –> drains into popliteal vein in popliteal fossa
deep venous drainage
venae comitantaes (accompany arteries) merge at the junction of the anterior and posterior tibial arteries –> popliteal vein –> passes through adductor magnus and merges with great saphenous vein –> femoral vein –> passes behind inguinal ligament to become external iliac vein
what is compartment syndrome
swelling of leg muscles causing pain and compression of nerves and vessels
caused by direct trauma, burns, prolonged immobilisation, excessive exercise, dehydration, rhabdomyolysis or diabetes mellitus
what is a varicose vein
a vein that has a larger diameter than normal and is elongated and tortuous
caused by weakness of vein walls, incompetent valves, elevated intra-abdominal pressure, damaged endothelium or abdominal tumours
what is deep vein thrombosis
venous stasis causing unilateral pain and swelling, tenderness and cramping, skin discolouration and leg fatigue –> may cause pulmonary thromboembolism and hence is a medical emergency
caused by incompetent loose fascia, external pressure on veins, muscular inactivity, thrombophlebitis
superficial lymphatic drainage
accompany saphenous vein to eventually drain into lumbar lymphatic trunk
for great saphenous vein they end in the superficial inguinal lymph nodes and pass along to external iliac lymph nodes
for small saphenous they enter popliteal lymph nodes
deep lymphatic drainage
accompany deep veins to reach deep inguinal lymph nodes, pass to external and common iliac lymph nodes, eventually draining into lumbar lymphatic trunks
what are the 6 Ps of acute limb ischaemia?
pain, pallor, pulselessness, paralysis, paraaesthetia (numbness), perishingly cold
femoral triangle boundaries
superior: inguinal ligament
lateral: sartorius
medial: adductor longus
roof: fascia and skin of thigh
floor: iliopsoas, pectineus, adductor longus
femoral triangle contents (NAVEL)
femoral Nerve
femoral Artery
femoral Vein
Empty space (femoral canal)
Lymph vessels and deep inguinal lymph nodes
AVEL are enclosed in the femoral sheath
popliteal fossa boundaries
lateral: biceps femoris, lateral head of gastrocnemius, plantaris
medial: semitendinosus, semimembranosus, medial head of gastrocnemius
roof: superficial and deep fascia of thigh
floor: popliteal surface of femur, posterior ligament of knee, popliteus
popliteal fossa contents (Serve And Volley Next Ball)
medial to lateral:
Semimembranosus and Semitendinosus
popliteal Artery
popliteal Vein and tributary (small saphenous vein)
tibial Nerve and fibular Nerve
Biceps femoris
