9 lumbosacral plexus

Question 1

what’s the key nerve of the lumbosacral plexus ?

Answer 1

sciatic nerve

Question 2

What regions are the nerve plexus ?

Answer 2

where the ventral rami of spianl nerves join and exchange neurons

Question 3

which plexuses supply the lower limbs ?

Answer 3

lumbar (T1-L4)
sacral (L4-S4)

Question 4

Which muscles of the thigh does the lumbar plexus innervate ?

Answer 4

anterior and medial

Question 5

Which anterior primary rami does the lumbar plexus originate from ?

Answer 5

T1-L4

Question 6

Where does a majority (except for 2) of the branches of the lumbar plexus pass through ?

Answer 6

substance os psoas major and emerge at its lateral border

Question 7

what are the 2 nerves that emerge at the medial border ?

Answer 7

• genitofemoral
• obturator

Question 8

which muscle is a useful landmark in relation to the lumbar plexus ?

Answer 8

psoas muscle

Question 9

List the important nerves that supply the lower limbs :

Answer 9

• femoral N. (L2,3,4)
• obturator N. (L2,3,4)
• lumbosacral trunk (L4,5)
• lateral cutaneous nerve of the thigh (L2,3)

Question 10

what does femoral nerve supply ?

Answer 10

anterior muscles of thigh

Question 11

what does obturator nerve supply ?

Answer 11

medial (adductors) of the thigh

Question 12

what does lumbosacral trunk largely contribute to ?

Answer 12

sciatic nerve

Question 13

What happens in condition called meralgia paraesthetica ?

Answer 13

lateral cutaneous nerve of thigh can get trapped under the inguinal ligament

causing pain and paraesthesia to lateral aspect of thigh

Question 14

what are the 2 branches of the scaitic nerve ?

Answer 14

• common peroneal (fibular) nerve
• tibial nerve

Question 15

Which spinal nerves does sciatic nerve arise from ?

Answer 15

L4
L5
S1
S2
S3

Question 16

what nerves are included in lumbosacral plexus ?

Answer 16

predominately sciatic nerve + S4

Question 17

which nerve can give the trendelenburg gait ?

Answer 17

L5 radiculopathy

Question 18

what are branches of the lumbosacral plexus ?

Answer 18

• superior gluteal N. (L4,L5,S1)
• inferior gluteal N. (L5,S1,S2)
• posterior cutaneous N. (S1,S2,S3)
• pudendal N. (S2,S3,S4)

Question 19

Which muscles are innervated by the superior gluteal nerve ?

Answer 19

• gluteus medius
• gluteus minimus
• tensor fascia lata muscles

Question 20

which muscle is innervated by inferior gluteal nerve ?

Answer 20

gluteus maximus muscle