Nervous System - General Principles of Nerve Supply

Question 1

What happens to a nerve once it supplies a structure in an embryo?

Answer 1

It never alters it’s course. Wherever the structure in the fetus goes it brings the nerve with it.

Question 2

What inner ages skeletal muscles?

Answer 2

Motor neuron pools.

Question 3

What are motor neuron pools?

Answer 3

Groups of motor nerve cell bodies in certain cranial nerve nuclei of the brain stem and anterior horns of the spinal cord.

Question 4

How are their motor neuron pools arranged?

Answer 4

The pool that supplies one muscle overlays the pool that supplies that other.

Question 5

Where will you not see the arrangement of motor neuron pools and muscles?

Answer 5

C4 and C6 nerves since they only supply one muscle - superior oblique and lateral recuts of the eye).

Question 6

Are limb muscle nerves purely motor?

Answer 6

No - they contain afferent sensory fibres for proprioception.

Question 7

Where do the nerves go from the posterior rami?

Answer 7

Pass backwards and supply the extensor muscles of the vertebral column and skull and the skin that overlies them (to an extent).

Question 8

Where do the nerves go from the anterior rami?

Answer 8

Supply all muscles of trunk, limbs and skin at sides and front of the neck and body.

Question 9

What does the posterior rami of the spinal nerves supply?

Answer 9

1. Erector spinal muscles.
2. Transversospinalis groups (lie deep to thoracolumbar fascia).
3. Lavatory costae muscles of the thorax.

Question 10

What does each posterior rami divide into?

Answer 10

1. Medial branch.
2. Lateral branch.

Question 11

What do the branches of the posterior rami supply?

Answer 11

Both medial and lateral supply muscle. But only one branch will reach and supply the skin.

Question 12

Does C1 have a cutaneous branch?

Answer 12

No.

Question 13

DO the posterior rami of the 12 Thoracic nerves and 5 sacral nerves supply skin?

Answer 13

Yes.

Question 14

Describe the exception with the posterior rami and the spinal nerves?

Answer 14

Posterior rami of lower two cervical and lumbar nerves do not reach the skin.

Question 15

Which branches of the posterior rami supply the skin?

Answer 15

1. Medial - upper half of the body.
2. Lateral - lower half of the body.

Question 16

Do nerves of posterior ramus supply skin or muscles in limbs?

Answer 16

No.

Question 17

What does the anterior rami supply?

Answer 17

1. Pre-vertebral flexor muscles segmentally by separate branches from each nerve.

Question 18

What anterior rami supply the muscles of the body wall?

Answer 18

12 thoracic nerves and L1.

Question 19

What is the pathway for the intercostal nerves?

Answer 19

Each nerve supplies the muscles of the intercostal space and the lower six nerves pass beyond the costal margin to supply the muscles of the antihero abdominal wall.

Question 20

What is the lowest spinal nerve to supply the anterior abdominal wall?

Answer 20

L1 - ilihypogastric and ilioingual nerves.

Question 21

What anterior rami supply skin in the neck?

Answer 21

C2-C4. Innervated by the cervical plexus.

Question 22

What anterior rami supply skin in the upper limb?

Answer 22

C5-8 and T1. Innervated via the brachial plexus.

Question 23

What anterior rami supply the skin in the funk?

Answer 23

T2-L1 - in strips of zones in regular sequence.

Question 24

How do the lower 6 thoracic nerves supply the skin of the abdominal wall?

Answer 24

Pass beyond the costal margin obliquely downwards.

Question 25

What does each anterior ramus do?

Answer 25

Supplies a strip of skin that overlies it (dermatology).

Question 26

What does each spinal nerve contain?

Answer 26

Mixture of sensory and motor fibres.

Question 27

Where is the neurovascular plane?

Answer 27

The neurovascular bundle spirals around the walls of the thorax and abdomen in a plane between the middle and deepest of the three muscle layers.

Question 28

Where are the nerves in the neurovascular plane?

Answer 28

Below the arteries around the body wall, but cross the arteries posterior lay alongside the vertebral column and again anteriorly near the ventral midline.

Question 29

Where does the nerve always lie?

Answer 29

Closer to the skin.

Question 30

Where does the sympathetic trunk lay?

Answer 30

Not in the neurovascular plane, but runs vertically within the arterial circle.

Question 31

What makes up the arterial circle?

Answer 31

1. Aorta.
2. Intercostal arteries.
3. Lumbar arteries.
4. Interbank thoracic.
5. Superior and inferior epigastric arteries.

Question 32

Where do the spinal nerves run?

Answer 32

• Come out from the intervertebral for Amin’s.
• Pass laterally behind vertebral artery in the neck.
• Pass behind the posterior inter-costal arteries in the thorax.
• Pas behind the lumbar arteries in the abdomen.
• Pass behind the lateral sacral artery in the pelvis.

Question 33

Where do the anterior terminal branches of the spinal nerves pass?

Answer 33

In front of the internal thoracic and superior/inferior epigastric arteries.

Question 34

What lies posterior to the sympathetic trunk?

Answer 34

Segmental vessels - vertebral, posterior, intercostal, lumbar and lateral sacral arteries.

Question 35

What do sympathetic fibres do?

Answer 35

They are the main vasoconstrictor in function. Main function is temperature regulation.