nerves of lower limb

Question 0

where is the lumbar plexus

Answer 0

within the substance of psoas major muscle

Question 1

two plexuses of the lower limb

Answer 1

sacral and lumbar

Question 2

which ventral rami form the lumbar plexus

Answer 2

L1-4

Question 3

what are the 3 divisions emerging from the lateral surfae of the lumbar plexus as they emerge from psoas

Answer 3

• iliohypogastric and ilioinguinal nerves (ilioinguinal is like a branch of iliohypogastric) - lateral cutaneous nerve of thigh - femoral nerve

Question 4

which ventral rami contribute to the iliohypogastric and ilioinguinal nerves

Answer 4

L1

Question 5

what is the sensory innervation of the ilioinguinal and iliohypogastric nerves

Answer 5

cutaneous supply of the skin over the inguinal region and the front of the scrotum

Question 6

what is the motor innervation of the iliohypogastric and ilioinguinal nerves

Answer 6

• the lowermost fibres of internal oblique and transversus abddominus

Question 7

which ventral rami contribute to the lateral cutaneous nerve of thigh

Answer 7

L2 and L3

Question 8

what is the sensory innervation of the lateral cutaneous nerve of thigh

Answer 8

supplies the skin of the lateral part of the thigh

Question 9

route of the lateral cutaneous nerve of thigh

Answer 9

emerge from the lateral border of psoas major and onto iliacus –> beneath the inguinal ligament and into the anterior compartment of the thigh

Question 10

which ventral rami contribute to the femoral nerve

Answer 10

L2,3,4

Question 11

onto what surface does the femoral nerve go onto of the thigh

Answer 11

the anterior compartment

Question 12

which nerve of the lumbar plexus emerges from the anterior surface of psoas

Answer 12

genitofemoral nerve

Question 13

which ventral rami contribute to the genitofemoral nerve

Answer 13

L1,2

Question 14

what does the femoral branch of the genitofemoral nerve supply

Answer 14

sensory supply to the area of skin immediately beneath the middle of the inguinal ligament

Question 15

what does the genital branch of the genitofemoral nerve supply

Answer 15

the sensory supply to the spermatic cord

Question 16

which nerve of the lumbar plexus emerges from the medial border of psoas

Answer 16

obturator

Question 17

which ventral rami contribute to the obturator nerve

Answer 17

L2,3,4

Question 18

what are all the nerves of the lumbar plexus

Answer 18

iliohypogastric and ilioinguinal nerves lateral cutaneous nerve of thigh femoral nerve genitofemoral nerve obturator nerve

Question 19

which nerves contribute to the sacral plexus

Answer 19

S1-4 (and also what is left of L4 and L5)

Question 20

where is the sacral plexus

Answer 20

formed on the surface of piriformis on the posterior wall of the pelvis

Question 21

what is the motor innervation of the femoral nerve

Answer 21

to quads, sartorius and pectineus (muscles of the anterior thigh)

Question 22

what is the sensory innervation of femoral nerve

Answer 22

• anteromedial thigh (via anterior cutaneous branches) - medial side of knee, leg and ankle (saphenus nerve)

Question 23

what other innervation, other than sensory and motor, does the femoral nerve do

Answer 23

articular branches to hip and knee

Question 24

what is the positioning of the femoral nerve as it passes beneath the inguinal ligament and into the anterior compartment of the thigh

Answer 24

it is lateral to vascular structures, OUTSIDE the femoral sheath

Question 25

where abouts does the femoral nerve branch into its terminal branches

Answer 25

about 2.5cm below the inguinal ligament

Question 26

which group of muscles does the obturator nerve supply

Answer 26

the adductor muscles (medial)

Question 27

describe the route of the obturator nerve

Answer 27

emerges from medial border of psoas --\> drops onto lateral wall of pelvis --\> through obturator canal --\> medial compartment of thigh

Question 28

which muscles specifically does the obturator nerve supply

Answer 28

adductor longus and brevis - via anterior division adductor magnus and gracilis - via posterior division and pectineus

Question 29

where is the sensory innervation of the obturator nerve

Answer 29

sensory to inferomedial thigh (just above the medial side of knee)

Question 30

what other supply does the obturator nerve do apart from sensory and motor

Answer 30

articular branches to hip

Question 31

which two branches of the sacral plexus contribute to the innervation of the leg

Answer 31

posterior cutaneous nerve of thigh sciatic nerve

Question 32

what is the supply of the posterior cutaneous nerve of thigh

Answer 32

sensory supply over the back of the thigh

Question 33

what are the two "components" of the sciatic nerve

Answer 33

tibial nerve common fibular nerve

Question 34

what is the route of the sciatic nerve through the leg

Answer 34

exits pelvis via greater sciatic foramen --\> emerges beneath piriformis, onto the posterior of the hip joint --\> descends in the posterior thigh under biceps femoris and on obturator internus and gemeli --\> divides into terminal branches at the apex of the popliteal fossa

Question 35

which type of hip dislocation can take out the sciatic nerve

Answer 35

posterior

Question 36

what is the motor innervation of the sciatic nerve

Answer 36

to the hamstrings (via the tibial component of sciatic nerve - apart from SHOB)

Question 37

what articular branches does the sciatic nerve give

Answer 37

articular branches to hip

Question 38

which rami contribute to the tibial nerve

Answer 38

L4-5, S1-3

Question 39

the tibial nerve is the nerve of which compartment of the leg

Answer 39

the posterior compartment (calf - flexors)

Question 40

what is the route of the tibial nerve

Answer 40

continues the vertical descent of sciatic nerve through the popliteal fossa behind the knee joint --\> beneath fibrous arch of Soleus --\> descends between the superficial and deep muscles of the calf on tibialis posterior --\> posterior to medial malleolus --\> sole of foot --\> divides into medial and lateral plantar nerves

Question 41

what is the motor innervation of the tibial nerve

Answer 41

the to posterior muscles of the leg

Question 42

what is the sensory innervation of the tibial nerve

Answer 42

posterior leg and lateral side of foot - sural nerve sole of foot - medial calcaneal, medial and lateral plantar nerves

Question 43

which part of the sole of the foot is supplied by the saphenous nerve

Answer 43

very medial part

Question 44

what is the route of the common fibular nerve

Answer 44

remains next to (medially) biceps femoris --\> superficial to lateral head of gastrocnemius on route --\> winds around the neck of fibula --\> into substance of fibularis longus --\> divides into terminal branches (deep and superficial fibular nerves)

Question 45

if you take out the common fibular nerve what is the sign

Answer 45

"Foot drop"

Question 46

what is the motor innervation of the common fibular nerve

Answer 46

nothing

Question 47

what is the sensory innervation of the common fibular nerve

Answer 47

- sensory to upper lateral leg via sural cutaneous nerve - gives communicating branch to sural nerve (from tibial nerve)

Question 48

which nerve roots contribute to the common fibular nerve

Answer 48

L4-5, S1-2 (no S3)

Question 49

the common fibular nerve is the nerve of which compartment

Answer 49

the anterior compartment of the leg (extensors)

Question 50

two divisions of the common fibular nerve

Answer 50

deep and superficial fibular nerves

Question 51

route of the deep fibular nerve

Answer 51

begins in substance of fibularis longus --\> descends deep to EDL, anterior to interosseous membrane --\> beneath extensor retinaculum -\> dorsum of the foot --\> between toe cleft of 1st and 2nd toes

Question 52

motor innervation of deep fibular nerve

Answer 52

anterior compartment of the leg - tibialis anterior, EDL, EHL extensor digitorum brevis (on dorsum of the foot)

Question 53

what is the sensory innervation of the deep fibular nerve

Answer 53

sensory to the skin between the 1st and 2nd toes

Question 54

what is the motor innervation of the superficial fibular nerve

Answer 54

lateral compartment of the leg - fibularis longus and brevis

Question 55

what is the sensory innervation of the superficial fibular nerve

Answer 55

lower lateral leg and dorsum of the foot (sparing the first web space)

Question 56

explain the innervation of the muscles in the gluteal region

Answer 56

superior gluteal nerve - supplies gluteus minimus and medius inferior gluteal nerve supplies gluteus maximus

Question 57

which nerves innervate the anterior, medial and posterior compartments of the thigh

Answer 57

anterior - femoral medial - obturator posterior - sciatic nerve

Question 58

how do you get a dermatomal or myotomal disruption to the lower limb

Answer 58

disruption of the nerves at the root level

Question 59

what are the roots of the superior and inferior gluteal nerves

Answer 59

superior - L5,5,S1 - emerges above piriformis inferior - L5, S1,2 - emerges below piriformis