review of lower limb nerves/vessels

Question 1

innervation to lower limb

Answer 1

comes from lumbosacral plexus- femoral nerve supplies anterior thigh, obturator medial thigh, sciatic rest (posterior thigh, leg and foot)

Question 2

anterior/posterior divisions

Answer 2

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

Question 3

importance of piriformis

Answer 3

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)

Question 4

importance of common peroneal nerve

Answer 4

goes around neck of fibula, so vulnerable to damage

Question 5

saphenous nerve and sural nerve

Answer 5

major branch of femoral nerve- cutaneous for medial leg/foot, whereas sural cutaneous for lateral leg/foot

Question 6

DIAGRAM from which roots do posterior cutaneous nerve emerge from

Answer 6

S1-2, as S1-2 supplies most region of posterior thigh AND leg

Question 7

DIAGRAM autonomous sensory zones

Answer 7

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

Question 8

DIAGRAM cutaneous innervation of foot with clinical significance

Answer 8

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

Question 9

prolapsed intervertebral disc at L5-S1 effects

Answer 9

motor- no eversion sensory- lateral edge of foot lost reflex- loss of ankle jerk (S1) minimal autonomic effects

Question 10

what occurs with lesion at common peroneal nerve at fibular neck

Answer 10

motor- foot drop sensory- affects dorsum of foot no effect on reflexes/autonomic

Question 11

effect of foot drop

Answer 11

leads to high stepping gait, and damage to sole due to pressure (aka TROPHIC DAMAGE- damage to surrounding tissue)

Question 12

trifurcation of popliteal artery

Answer 12

anterior tibial artery (gives off dorsalis pedis artery) posterior tibial peroneal artery

Question 13

only branch of internal iliac that goes into thigh

Answer 13

obturator artery

Question 14

pulses in leg

Answer 14

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

Question 15

posterior tibial artery

Answer 15

goes behind medial malleolus

Question 16

arteries of foot

Answer 16

lateral and medial plantar artery, and dorsalis pedis artery for dorsum

Question 17

superficial veins+ pathway

Answer 17

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

Question 18

venae comitantes

Answer 18

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

Question 19

how to get fluid into body in leg, and what method preferred now

Answer 19

saphenous vein cut above medial malleolus- get fluid into body: occurs when venous cannulation not possible now put fluids in intraosseously (ie anterior tibia)

Question 20

INTERMITTENT claudication vs acute limb ischaemia, cause, and muscle mainly affected

Answer 20

sudden occlusion = acute limb ischaemia GRADUAL occlusion= intermittent claudication (muscle pain upon exertion), usually due to ARTERIAL embolism affects calf usually

Question 21

compartment syndrome

Answer 21

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

Question 22

acute compartment syndrome vs chronic

Answer 22

often caused by trauma, where emergency fasciotomy needed (ie compartment opened up) to relieve pressure and prevent muscle death chronic due to exercise

Question 23

important clinical point about lower limb veins- varicose veins,

Answer 23

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)

Question 24

how venous flow is supported, what occurs if not and treatment for it

Answer 24

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)

Question 25

DIAGRAM remembering dermatomes

Answer 25

L3 to knee (front on thigh) L4 to the floor (medial front of leg) L5 (lateral front of leg and big toe) S1- lateral part of foot (little toe) S2- most of posterior leg.thigh S3,4,5- perianal region (S3,4,5, shits coming alive)

Question 26

rule of motor segmention for JOINTS

Answer 26

the more distal the joint, the more CAUDAL the segment (ie ankle supplied by lower spinal cord than hip joint)

Question 27

autonomic function of lower limbs

Answer 27

SNS from T11-2, not any PNS

Question 28

reflex arcs in lower limb/upper limb and muscles worked, and way to remember

Answer 28

ankle (S1-2)- tap calcaneal tendon (gastric, soleus and plantaris work) knee (L3,4)- tap patellar tendon (quadriceps) biceps (C5,6) triceps (C7,8) COUNT TO 8

Question 29

damage to femoral nerve

Answer 29

rarely damage, but can occur during hip replacements/inguinal hernia repair

Question 30

damage to lateral cutaneous nerve of thigh

Answer 30

can be compressed at level of inguinal ligament near ASIS= meralgia paraesthetica

Question 31

damage to obturator nerve

Answer 31

rarely damaged, but cutaneous damage= pelvic disease

Question 32

damage to superior gluteal nerve

Answer 32

causes trendelenbergs gait, can occur during hip replacement (nerve near greater trochanter)

Question 33

damage to sciatic nerve

Answer 33

due to hip replacement- common peroneal more vulnerable than tibial, as tibial deep

Question 34

damage to saphenous

Answer 34

damaged when cut at medial malleolus, or during ACl surgery at knee

Question 35

NAVY-femoral triangle and clinical significance

Answer 35

lateral to medial - nerve, artery, vein artery used during heart surgery, femoral vein used for resuscitation

Question 36

deep drainage of leg

Answer 36

anterior and posterior tibial veins, as well as peroneal veins dorsal venous arch drain into anterior tibial vein, plantar drains into posterior tibial vein

Question 37

deep drainage of leg to popliteal

Answer 37

tibial veins and peroneal vein drain into popliteal vein

Question 38

deep drainage of popliteal to iliac

Answer 38

popliteal veins runs along popliteal artery to drain into femoral vein (also receives venae comitantes of profundal femoris vein ie profundal femoris vein) femoral vein (medial to artery) forms external iliac vein

Question 39

which DVT more dangerous

Answer 39

proximal DVT more dangerous (more risk of PE)

Question 40

superficial thrombophelbitis

Answer 40

superficial veins clot= painful, but not as dangerous as DVT

Question 41

venous grafts

Answer 41

used in arterial bypass surgery, where part of vein used to bypass blocked part of artery

Question 42

why venous graft not a problem

Answer 42

good anastomosis in leg, so removing superficial veins not so bad