Nerve Supply of the Body Wall

Question 1

Which nerves supply the body wall as a whole

Answer 1

12 thoracic spinal nerves and first lumbar spinal nerve

Question 2

end of the spinal cord

Answer 2

ends at L1
Cauda equina continues after

Question 3

where does a spinal nerve begin

Answer 3

where sensory and motor roots of spinal cord

Question 4

anterior root vs posterior root

Answer 4

anterior is efferent - motor neurons

posterior is afferent - sensory neurons, ganglion present where cell bodies are concentrated

Question 5

why does the anterior root of a spinal nerve have no ganglion

Answer 5

motor neuron cell bodies are in the grey matter of the spinal cord

Question 6

what does a spinal nerve branch into
what do they supply

Answer 6

anterior and posterior ramus
supply front and back, ant and pos regions supplied by that nerve

Question 7

where do spinal nerves emerge from the vertebral column

Answer 7

intervertebral foramen between pedicles

Question 8

three layers of spinal meninges from outer to inner

Answer 8

Dura matter
Arachnoid matter
Pia matter

Question 9

Denticulate ligaments role

Answer 9

prevent lateral movement of spinal cord

Question 10

meningitis

Answer 10

inflammation of meninges

Question 11

Dura mater and epidural space

Answer 11

tough fibre (dense collagen)
epidural space between dura matter and vertebral canal, anaesthesia

Question 12

arachnoid and subarachnoid space

Answer 12

between dura and pia
subarachnoid space is filled with CSF
location of lumbar punctures (medical test)

Question 13

pia mater

Answer 13

elastic and collagen fibre bound to neural tissue

Question 14

organisation of spinal cord

Answer 14

inner grey matter with H shaped horns (projections towards outer surface)
median white and grey commissures
columns of white matter
anterior fissure and posterior sulci

Question 15

what do motor fibres connect

Answer 15

muscles to lower motor neuron in ventral horn of spinal cord

Question 16

what do sensory fibres connect

Answer 16

skin and deep tissues to sensory neuron in dorsal root ganglion

Question 17

rami communicans

Answer 17

point of connection between pre-ganglionic fibre (ramus) and sympathetic trunk

Question 18

post ganglionic sympathetic fibres

Answer 18

connect sympathetic trunk to organs
rejoin spinal nerve and are distributed via dorsal or ventral ramus to body wall

Question 19

what do sympathetic fibres supply in the skin

Answer 19

blood vessels
sweat glands
arrectores pilorum

Question 20

anterior ramus

Answer 20

each runs a separate course forward
supplies the skin muscles and serous membranes of thoracic and abdominal walls
some also supply limbs

Question 21

dorsal ramus

Answer 21

passes backward and supplies muscles, bones, joints and skin of the back

Question 22

overlap of thoracic nerves

Answer 22

distribution of ventral rami is segmental
but overlap is so great that the section above and below is needed to complete anaesthesia and paralysis of the middle one

Question 23

dermatome

Answer 23

segment of skin innervated by a specific spinal nerve

Question 24

why does shingles show up only on one dermatome

Answer 24

virus reactivation travels to the skin retrogradely from the DRG

Question 25

intercostal nerves

Answer 25

ventral rami of the first 11 thoracic spinal nerves
run along subcostal grooves

Question 26

which ventral rami give branches to the upper limb as well as the thoracic wall

Answer 26

1st to 3rd

Question 27

why are T4-6 spinal nerves called typical

Answer 27

they only supply the thorax and not the limbs or anterior body wall

Question 28

referred pain
what causes it

Answer 28

pain from the internal organs and body wall that is felt elsewhere
because they share the same subsequent pathway to the brain

Question 29

which ventral rami are thoraco-abdominal
which ventral ramus is subcostal rather than intercostal

Answer 29

7th - 11th
12th

Question 30

where do lateral cutaneous branches of intercostal ribs arise
what do they supply

Answer 30

at the angle of of the rib
supply the skin and subcutaneous tissue of the thorax

Question 31

which nerves are the thoracoabdominal nerves
why are they different to the typical intercostal nerves

Answer 31

7th - 11th
they supply the thoracic wall and the abdominal wall as well

Question 32

location and function of the thoracoabdominal nerves

Answer 32

between transversus and internal oblique muscles, continue behind rectus abdominus

supply the muscles of body wall for trunk movement, forced expiration and increasing abdominal pressure

Question 33

iliohypogastric and ilioinguinal nerves

Answer 33

derived chiefly from the first lumbar nerve (L1)

iliohypogastric innervates muscle and skin of abdominal region

ilioinguinal innervates the transverse abdominis and internal oblique muscles