lower limb nerves

Question 1

lumbar plexus nerves (Interested In Getting Laid On Fridays)

Answer 1

Iliohypogastric L1
Ilioinguinal L1
Genitofemoral L1 L2
Lateral femoral cutaneous L2 L3
Obturator L2 L3 L4
Femoral L2 L3 L4

Question 2

tendon tests for nerve roots

Answer 2

patellar/quadriceps reflex: L2, L3, L4
ankle jerk reflex (Achilles tendon): S1, S2

Question 3

sciatic nerve supply

Answer 3

L4-S3, supplies the posterior compartment of the thigh, divides into tibial and fibular nerves

Question 4

tibial nerve supply

Answer 4

S1-S2, passes through soleus to supply posterior leg muscles, then passes behind medial malleolus to split into medial and lateral plantar nerves

Question 5

fibular nerve supply

Answer 5

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

Question 6

obturator nerve supply

Answer 6

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

Question 7

femoral nerve supply

Answer 7

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

Question 8

saphenous nerve supply

Answer 8

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

Question 9

medial plantar nerves supply

Answer 9

runs with medial plantar artery to supply medial 3.5 toes, 1st lumbrical, abductor hallucis, flexor digitorum brevis

Question 10

lateral plantar nerve supply

Answer 10

runs with lateral plantar artery to supply lateral 1.5 toes, lumbricals 2-4, abductor digiti minimi, all interossei

Question 11

superficial peroneal nerve supply

Answer 11

lateral leg muscles, skin of anterolateral leg surface and dorsum of foot

Question 12

deep peroneal nerve supply

Answer 12

pierces the anterior septum to supply anterior leg muscles, lies lateral to anterior tibial artery, enters dorsum of foot lateral to dorsalis pedis artery

Question 13

sciatic nerve lesions presentation

Answer 13

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

Question 14

what does dry hot red autonomic loss of nerve supply mean

Answer 14

flushed skin due to lack of vasoconstriction, hair unable to stand due to paralysed erector pilli

Question 15

fibular nerve lesions presentation

Answer 15

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

Question 16

femoral nerve lesions presentations (rare though)

Answer 16

sensory loss: anterior and medial thigh, medial leg down to big toe
motor loss: loss of knee flexion
autonomic loss: dry, hot, red

Question 17

tibial nerve lesions presentation (rare bc nerve runs deep)

Answer 17

sensory loss: sole of foot
motor loss: posterior leg muscles and plantar flexion, opposing muscles dorsiflex and evert foot
autonomic loss: dry, hot, red

Question 18

lower limb dermatomes

Answer 18

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

Question 19

femoral artery branches (perform extreme cramming, pathetic profs)

Answer 19

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

Question 20

femoral artery supply

Answer 20

anterior and anteromedial aspects of thigh

Question 21

profunda femoris supply

Answer 21

medial, posterior and lateral part of thigh

Question 22

obturator artery supply

Answer 22

anterior and posterior branches encircle the obturator foramen, supplies the head of the femur

Question 23

anterior tibial artery supply

Answer 23

becomes the dorsalis pedis at the ankle
supplies the anterior compartment of the leg and dorsum of the foot

Question 24

posterior tibial artery supply

Answer 24

branch of the popliteal artery, branches into peroneal, medial and plantar arteries, supplies the posterior compartment of the leg and sole of the foot

Question 25

arterial supply to the foot

Answer 25

plantar artery (branch of posterior tibial artery) gives branches supplying each toe dorsalis pedis (branch of anterior tibial artery) supplies the foot

Question 26

how to calculate ankle brachial index

Answer 26

arm blood pressure over ankle blood pressure (if <1: narrow ankle blood vessels and claudication)

Question 27

venous drainage of the great saphenous vein

Answer 27

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

Question 28

venous drainage of small saphenous vein

Answer 28

dorsal digital vein of 5th toe + dorsal venous arch --> ascends posterior to lateral malleolus --> drains into popliteal vein in popliteal fossa

Question 29

deep venous drainage

Answer 29

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

Question 30

what is compartment syndrome

Answer 30

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

Question 31

what is a varicose vein

Answer 31

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

Question 32

what is deep vein thrombosis

Answer 32

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

Question 33

superficial lymphatic drainage

Answer 33

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

Question 34

deep lymphatic drainage

Answer 34

accompany deep veins to reach deep inguinal lymph nodes, pass to external and common iliac lymph nodes, eventually draining into lumbar lymphatic trunks

Question 35

what are the 6 Ps of acute limb ischaemia?

Answer 35

pain, pallor, pulselessness, paralysis, paraaesthetia (numbness), perishingly cold

Question 36

femoral triangle boundaries

Answer 36

superior: inguinal ligament lateral: sartorius medial: adductor longus roof: fascia and skin of thigh floor: iliopsoas, pectineus, adductor longus

Question 37

femoral triangle contents (NAVEL)

Answer 37

femoral Nerve femoral Artery femoral Vein Empty space (femoral canal) Lymph vessels and deep inguinal lymph nodes AVEL are enclosed in the femoral sheath

Question 38

popliteal fossa boundaries

Answer 38

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

Question 39

popliteal fossa contents (Serve And Volley Next Ball)

Answer 39

medial to lateral: Semimembranosus and Semitendinosus popliteal Artery popliteal Vein and tributary (small saphenous vein) tibial Nerve and fibular Nerve Biceps femoris