Lumbar and lumbosacral plexi

Question 1

lumbar plexus is formed by…

Answer 1

the ventral rami of spinal nerves L1-L4

Question 2

Cut. distribution of the lumbar plexus?

Answer 2

includes the skin of the lower abdomen, anterior, medial, and lateral thigh, and the medial side of the leg.

Also innervates the skin covering the root of the penis and ant scrotum in males and the skin over the mons pubis and ant portion of the labia majora in females

Question 3

muscle innervation of the lumbar plexus?

Answer 3

muscles in the anterior and medial compartments of the thigh

Question 4

lumbosacral/sacral plexus formed by…

Answer 4

the ventral rami of L4-S4

Question 5

cut distribution of the sacral plexus

Answer 5

post thigh, all of the leg and foot, perineum

Question 6

muscle innervation of the sacral plexus

Answer 6

musles of the gluteal region, perineum, post thigh (hamstrings), leg, and intrinsic muscles of the foot

Question 7

Clunial nerves

Answer 7

latin for butt. nerves constitute the cut. distribution of the gluteal region

1. superior cluneal nerves
2. middle clunial nerves
3. inferior cluneal nerves

Question 8

superior cluneal nerves

Answer 8

derived from dorsal rami of L2 and 3. Supply the skin over the central and superior portion of this region

Question 9

middle cluneal nerves

Answer 9

derived from dorsal rami of S2,3,4. supply the medial portion of the buttock

Question 10

inferior cluneal nerves

Answer 10

branches from the posterior femoral cutaneous nerve of the thigh, which is a branch from the ventral rami of the sacral plexus. Supply the skin covering the inf portion of the butt

Question 11

Prganglionic sympathetic neirons are found..

Answer 11

only as far inferior as the L2 region of the spinal cord.

Question 12

the first 2 paravertebral lumbar ganglia

Answer 12

attached to the first 2 lumbar ventral rami via botha a white and grey ramus communicans.

Question 13

Paravertebral ganglion below L2

Answer 13

have grey ramus communicans only

Question 14

how do preganglionic sympathetic axons reach the lower lumbar and sacral ganglia?

Answer 14

preganglionic neurons in the lower thoracic and upper lumbar regions have axons that can descend down the chain before forming a synapse in addition to sunapsing in the ganglia in which they enter.

Question 15

formation of the lumbar plexus

Answer 15

ventral rami of spinal nerves L1-L4.

A contribution from the ventral ramus of T12 may join L1

Question 16

L1 ventral ramus branches

Answer 16

1. iliohypogastric nerve
2. ilioinguinal nerve

Question 17

iliohypogastric nerve

Answer 17

supplies the muscles forming the lower portion of the abdominal wall. sensory to the region of skin covering the abdominal wall above the pubic bone

Question 18

ilioinguinal nerve

Answer 18

muscles forming the lower portion of the abdominal wall

sensory to skin covering the root of the penis and anterior scrotum in the mons pubis and the ant labia in the female

Question 19

genitofemoral nerve

Answer 19

L1 and L2

Gential branch supplies cremaster muscle lining in the scrotum in males

femoral branch is cut to the skin of the upper thigh just under th ilioinguinal lig

Question 20

cremaster reflex

Answer 20

used to test the integrity of the L1 spinal nerve. Rubbing the skin comprising th L1 dermatome (ant scrotum of upper thigh) can lead to contraction of the cremaster muscle.

Seen as an attempt by the cremaster to retract the testicle back into the abdomen, humans cant do that tho!

Question 21

lateral femoral cutaneous nerve

Answer 21

made up of branches from L2 and 3. Cut to the skin covering the lateral thigh.

entrapped under inguinal ligament near ASIS

compression of this nerve can happen if your pants are too tight. leads to a burning sensation over lateral thigh known as meralgia peristatica

Question 22

fermoral nerve

Answer 22

L2,3,4

supplies innervation to the muscles in the anterior compartment of the thigh (quad femoris and sartorius)

medial leg: saphenous branch

cut from the laterial and medial thigh and medial leg

Question 23

obturator nerve

Answer 23

L2,3,4

motor to muscles in th medial compartment of thigh (hip adductors, obturator externus)

cut to small region along the medial thigh near knee

Question 24

Lumbosacral plexus cut distribution

Answer 24

posterior thigh

leg: ant and post
foot: dorsal and plantar surfaces

Question 25

Lumbosacral plexus motor distribution

Answer 25

gluteal muscles hamstrings all muscles in the leg and foot perineum

Question 26

lumbosacral trunk

Answer 26

Formed by contributions of both L4 and L5

Question 27

superior gluteal nerve

Answer 27

lumbosacral plexus branch L4 L5 S1 tensor fascia lata, gluteus med and min

Question 28

inferior gluteal nerve

Answer 28

lumbosacral plexus branch L5 S1 S2 glut max

Question 29

nerve to obturator internus

Answer 29

**lumbosacral plexus branch** L5 S1 S2 obturator internus and superior gemmellus

Question 30

nerve to quadrator femoris

Answer 30

lumbosacral plexus branch L4 L5 S1 quadrator femoris, inferior gemellus, as well and the hip joint

Question 31

pudendal nerve

Answer 31

S2 S3 S4 muscles associated with the external genitals and the sphincters of the anus and urethra

Question 32

**Sciatic nerve**

Answer 32

lumbosacral plexus branch L4 L5 S1 S2 S3 S4 hamstring muscles in the post thigh before dividing into terminal branches: tibial and common fibular nerves

Question 33

posterior femoral cutaneous nerve

Answer 33

lumbosacral plexus branch S1-3 skin of the post thigh and the popliteal region

Question 34

peripheral nerve lesion

Answer 34

more than 1 spinal segment associate. loss of function of muscle atrophy several associated dermatomes

Question 35

radiculopathy

Answer 35

one dermatome weakness of muscle sensation loss rescrticted to one area herniated disc is a common cause

Question 36

L1 L2 radiculopathy

Answer 36

dermatome: lower abdomen, upper thigh myotome: hip flexion

Question 37

L2 L3 radiculopathy

Answer 37

Derm: ant and med thigh myo: hip adduction, knee extension test: squat

Question 38

L4 Radiculopathy

Answer 38

medial leg inversion and supination of tarsal joints

Question 39

L5 radiculopathy

Answer 39

dorsum of foot hip adductors, dosiflexion of ankle test: heel walk, tendelenburg

Question 40

S1 radiculopathy

Answer 40

lateral and post leg ankle plantar flexion, eversion and pronation of tarsal joints test: toe walk

Question 41

disc herniation (3 types)

Answer 41

soft herniation hard disc combo

Question 42

soft herniation

Answer 42

nucleus pulposus breaks through the annulus fibrosis affects lumbar spine people 30-50 most susceptiable because the elasticity and water content decreases with age

Question 43

spinal cord lesion

Answer 43

widespread muscle paralysis and loss of sensation below site of lesion classified by the segments of the cord that still function ie. c5 lesion leans that all segments up to and including C5 are functioning