Nerves and blood supply of the lower limb

Question 1

What is a plexus

Answer 1

a plexus is a network, latin- plecture, means to intertwine- forms peripheral nerves.

Question 2

what is the lumbar plexus

Answer 2

L1-L5 at each level a peripheral spine nerve leaves, this produces neuro material which goes into the plexus, this then exits as a nerve

Question 3

what is a sacral plexus

Answer 3

Sacral plexus- S1-S5

Question 4

where is the spinal cord from

Answer 4

from the cervical region down to L1,2.

Question 5

what is the cauda equina

Answer 5

conus medullaris between L1 and L2, this goes to the cauda equina. This forms peripheral nerve that exit via intervertebral foramen, through the sacrum they exit via anterior sacral foramen- joint sacral plexus

Question 6

peripheral spinal nerves

Answer 6

emerges from spinal cord via a ventral (front) and dorsal (back) root. Dorsal root- carries sensory information to the spinal cord (dorsal root ganglia- contain the sensory cell bodies), ventral root- carries motor information from the anterior horn cells

Question 7

what are the anterior horn cells

Answer 7

to do with motor response

Question 8

what are dermatomes

Answer 8

area of the skin supplied by a single spinal nerve of spinal cord level

Question 9

what does each spinal nerve do

Answer 9

each spinal nerve carries somatic sensory information from specific areas of skin,

Question 10

outlets from the pelvis- inguinal tunnel

Answer 10

femoral nerve- L2,L3,L4

Question 11

outlets from the pelvis- greater sciatic foramen

Answer 11

sciatic nerve, gluteal nerve

Question 12

outlets from the pelvis- obturator canal

Answer 12

obturator nerve

Question 13

outlets from the pelvis- peripheral nerves

Answer 13

peripheral nerves from different origins (L1,L2 etc) join together to form plexus, these join together to share information and form a single nerve

Question 14

Main branches of the lumbosacral plexus

Answer 14

femoral nerve- saphenous nerve, obturator nerve, sciatic nerve- tibial nerve (medial and lateral plantar nerve), common peroneal nerve (deep and superficial), superior and inferior gluteal nerves

Question 15

what is the lumbar plexus

Answer 15

ventral rami of spinal nerves of T12-L4, lies within the posterior part of the psoas major, supplies the abdominal wall and lower extremities

Question 16

branches of the lumbar plexus- muscle branches

Answer 16

femoral nerve L2,L3,L4

Obturator nerve- L2,L3,L4

Question 17

branches of the lumbar plexus- other nerves

Answer 17

iliohypogastric, ilio-inguinal, genitofemoral, lateral cutaneous nerve of thigh

Question 18

femoral nerve

Answer 18

carries information from the anterior rami of L2-L4 and runs through psoas major and under the inguinal ligament lateral to the femoral artery and vein, to enter the femoral triangle on the anteromedial aspect of the thigh- splits into anterior and posterior divisions

Question 19

femoral nerve- branches into pelvis and distal to the inguinal ligament

Answer 19

iliacus, pectineus, inguinal ligament- saphenous nerve- cutaneous, supplying skin of the anteromedial aspect of leg and medial aspect of the foot

Question 20

anterior divisions of the femoral nerve

Answer 20

sartorius, intermediate cutaneous nerve of thigh, medial cutaneous nerve of thigh

Question 21

posterior division of femoral nerve

Answer 21

saphenous nerve and quadriceps

Question 22

obturator nerve

Answer 22

originates from ventral rami of L2-L4, runs through psoas major, emerging at medial border; passes down on obturator internus; exits pelvis through the obturator foramen

Question 23

what does the obturator nerve supply

Answer 23

adductor group, gracilis, pectineus obturator externus, medial side of thigh, knee and hip joint

Question 24

iliohypogastric nerve

Answer 24

originates from L1, innervates- skin over lower abdominal above the pubis and lower back and hip, transverse abdominis, inter and external obliques

Question 25

genitofemoral nerve

Answer 25

originates at L1-L2 innervates- anterior thigh inferior to inguinal region

Question 26

ilio-inguinal nerve

Answer 26

originates L1, innervates- skin of external genitalia, proximal medial aspect of thigh, transverse abdominis, obliques

Question 27

lateral cutaneous nerve of thigh

Answer 27

originates L2-L3- passes under the inguinal ligament medial to the ASIS, innervates- lateral skin of thigh

Question 28

what is meralgia paresthetica

Answer 28

it is a condition characterized by tingling, numbness and burning pain in the outer part of your thigh. The condition is caused by compression of the lateral femoral cutaneous nerve

Question 29

what is the sacral plexus

Answer 29

it arises from ventral rami of S1-S4, contribution from lumbar plexus (L4-L5), lies anterior to the piriformis muscle and posterior pelvic wall, exits via the greater sciatic notch

Question 30

branches of the sacral plexus

Answer 30

sciatic nerve, superior/ inferior gluteal nerve, quadratus femoris and gemellus inf, obturator internus and gemellus sup, piriformis

Question 31

sciatic nerve

Answer 31

largest nerve in the body- L4-S3, consists of 2 nerve bundles- tibial nerve and common peroneal nerve, leaves pelvis via greater sciatic notch, exits just inferior to piriformis

Question 32

sciatic nerve innervates

Answer 32

hamstrings, adductor magnus

Question 33

sciatic nerve route

Answer 33

passess vertically down the back of the thigh, lying on adductor magnus, covered by long head bicep femoris. it divides into common peroneal (wraps around the head of fibula) and tibial nerve (straight through knee joint) between hip and popliteal fossa

Question 34

superior gluteal nerve

Answer 34

fibres from L4,L5,S1, innervates- gluteus med and min, and TFL

Question 35

inferior gluteal nerve

Answer 35

fibres from L5,S1,S2, innervates gluteus maximus

Question 36

tibial nerve

Answer 36

fibres from L4-S3, innervates popliteus, plantaris, gastrocnemius, soleus, tibialis posterior, FHL, FDL, it gives a branch to the sural nerve

Question 37

what does the tibial nerve split into

Answer 37

medial and lateral plantar nerves

Question 38

what is the sural nervw

Answer 38

sensory nerve that supplies the skin over the lateral side of the lower third of leg, derives from branches from both tibial and common peroneal nerve

Question 39

lateral plantar nerve innervates

Answer 39

remaining deep muscles, lumbricals (2,3,4), interossei, adductor digiti minimis, adductor hallucis, sensory cutaneous- 5th toe and lateral half of 4th toe

Question 40

medial plantar nerve innervates

Answer 40

FDB, FHB, 1st Lumbrical, sensory cutaneous- skin medial to big toe, skin between 1st and 4th toes

Question 41

common peroneal nerve

Answer 41

fibres from L4-S2, wraps around neck of fibula, splits into deep and superficial peroneal nerves

Question 42

superficial peroneal nerve

Answer 42

peroneus longus/ peroneus brevis- lateral compartment, skin over lateral leg , splits into medial and lateral branches

Question 43

deep peroneal nerve

Answer 43

innervates dorsiflexors, tibialis anterior, EHL, EDL, peroneus tertius, ankle joint

Question 44

deep peroneal nerve lateral branch

Answer 44

EDB/ 2nd dorsal interossei, tarsal and MTP joint

Question 45

deep peroneal nerve medial branch

Answer 45

1st dorsal interossei, 1st tarsal and MTP joint, skin between big and second toe

Question 46

femoral artery

Answer 46

this is a major artery supplying the lower limb which is the contribution of the external iliac artery, the artery continues down the thigh in the femoral canal, continuous in the adductor hiatus and then becomes the popliteal artery posterior to knee

Question 47

what does the external iliac artery become the femoral. artery

Answer 47

as the vessel passes under the inguinal ligament and enters the femoral triangle

Question 48

popliteal artery

Answer 48

this is the major artery that supplies the leg and foot and enters the posterior compartment of the leg from the popliteal fossa. in the posterior compartment the popliteal artery divides into the anterior tibial artery and posterior tibial artery

Question 49

where can the popliteal artery be palpated

Answer 49

in the popliteal fossa

Question 50

lower limb arterial supply

Answer 50

popliteal artery splits into- posterior and anterior tibial arteries, and dorsal pedis

Question 51

anterior and posterior tibial artery

Answer 51

anterior- anterior aspect ankle between EHL and 1st tendon of EDL posterior- enters the foot through the tarsal tunnel on the medial side of the ankle and posterior medial malleolus

Question 52

what is the dorsalis pedis

Answer 52

this is the continuation of the anterior tibial artery as it crosses the ankle joint. the pulse could be palpated on the dorsal aspect of the foot palpitating the vessel against the tarsal bone between the tendons of FHL and FDL to second toe