Lumbar plexus

Question 1

where is the lumbar plexus located

Answer 1

located in the lumbar region, within the substance of the psoas major muscle and anterior to the transverse processes of the lumbar vertebrae.

Question 2

how is the plexus formed

Answer 2

by the anterior rami (divisions) of the lumbar spinal nerves L1, L2, L3 and L4.

Question 3

which other nerve contributes to the lumbar plexus

Answer 3

T12

Question 4

spinal nerves

Answer 4

The spinal nerves L1 – L4 form the basis of the lumbar plexus.

At each vertebral level, paired spinal nerves leave the spinal cord via the intervertebral foramina of the vertebral column.

Each nerve then divides into anterior and posterior nerve fibres.

Question 5

branches

Answer 5

The anterior rami of the L1-L4 spinal roots divide into several cords. These cords then combine together to form the six major peripheral nerves of the lumbar plexus. These nerves then descend down the posterior abdominal wall to reach the lower limb, where they innervate their target structures.

Question 6

name the six major peripheral nerves of the lumbar plexus in order

Answer 6

1. illiohypogastric nerve
2. illioinguinal
3. genitofemroal
4. lateral cutaenous
5. femroal
6. obturator

Question 7

acronynm for the lumbar plexus

Answer 7

Imogen gets leftovers on fridays

Question 8

The iliohypogastric nerve is the

Answer 8

first major branch of the lumbar plexus. Does not supply any structures in the lower limb so it is beyond the scope of this unit.

Question 9

Illiohypogastric roots

Answer 9

L1 with contributions from T12

Question 10

how to rememebr ilihypogastric comes before illioinguinal

Answer 10

H comes be fore I in the alphabet

Question 11

Ilioinguinal Nerve

Answer 11

The ilioinguinal nerve follows the same anatomical course as the larger iliohypogastric nerve. After innervating the muscles of the anterior abdominal wall, it passes through the superficial inguinal ring to innervate the skin of the genitalia and middle thigh.

Question 12

roots of the illioinguinal nerve

Answer 12

L1

Question 13

motor function of the illioinguinal nerve

Answer 13

Innervates the internal oblique and transversus abdominis.

Question 14

sensory function of the illioinguinal nerve

Answer 14

Innervates the skin on the superior antero-medial thigh. In males, it also supplies the skin over the root of the penis and anterior scrotum. In females, it supplies the skin over mons pubis and labia majora.

Question 15

genitofemoral nerve

Answer 15

After leaving the psoas major muscle, the genitofemoral nerve quickly divides into a genital branch, and a femoral branch.

Question 16

roots fo the genitofemoral nerve

Answer 16

L1, L2

Question 17

motor function of the genitofemoral nerve

Answer 17

The genital branch innervates the cremasteric muscle.

Question 18

Sensory Functions of the genitofemoral nerve

Answer 18

The genital branch innervates the skin of the anterior scrotum (in males) or the skin over mons pubis and labia majora (in females). The femoral branch innervates the skin on the upper anterior thigh.

Question 19

Lateral Cutaneous Nerve of the Thigh

Answer 19

This nerve has a purely sensory function. It enters the thigh at the lateral aspect of the inguinal ligament, where it provides cutaneous innervation to the skin there.

Question 20

roots of the Lateral Cutaneous Nerve of the Thigh

Answer 20

L2, L3

Question 21

motor function of Lateral Cutaneous Nerve of the Thigh

Answer 21

none

Question 22

sensory function of Lateral Cutaneous Nerve of the Thigh

Answer 22

Innervates the anterior and lateral thigh down to the level of the knee.

Question 23

roots of the obturator nerve

Answer 23

L2, L3, L4

Question 24

motor function fo the obturator nerve

Answer 24

Innervates the muscles: obturator externus, pectineus, adductor longus, adductor brevis, adductor magnus, gracilis.

Question 25

sensory function fo the obturator nerve

Answer 25

Innervates the skin over the medial thigh.

Question 26

roots of the femoral nerve

Answer 26

L2, L3, L4

Question 27

Motor function of the femoral nerve

Answer 27

Innervates the muscles: Illiacus, pectineus, sartorius, all the muscles of quadriceps femoris.

Question 28

sensory function of the femoral nerve

Answer 28

innervates the skin of the anterior thigh and medial leg

Question 29

draw out the Imogen gets lunch on fridays chart with the nerve root contributions

Answer 29