Nervous System - Nerve Supply of Limbs

Question 1

What are the three strips of the body wall?

Answer 1

1. Longitudinal.
2. Posterior.
3. Ventral.

Question 2

What supplies the longitudinal strip?

Answer 2

Posterior rami.

Question 3

What supplies the lateral strip?

Answer 3

Lateral branches of the anterior rami.

Question 4

What supplies the ventral strip?

Answer 4

Anterior terminal branches of anterior rami.

Question 5

Where do limb buds grow from?

Answer 5

Lateral strip.

Question 6

What do the lateral branches of the anterior rami form?

Answer 6

Anterior and posterior divisions of the lateral branches form - Plexuses for supply of the muscles and skin of the limbs.

Question 7

What does the posterior division of the lateral branches of the anterior rami form?

Answer 7

Extensor muscles and skin of the limbs.

Question 8

What does the anterior division of the lateral branches of the anterior rami form?

Answer 8

Flexor muscles and skin of the limbs.

Question 9

Where do the flexor and extensor compartments meet?

Answer 9

Pre-axial and post-axial borders of the limb.

Question 10

What marks the pre and post-axial borders of the limb?

Answer 10

Veins.

Question 11

What are the markers of the pre and post-axial borders in the upper limb?

Answer 11

1. Cephalon vein = pre-axial border.
2. Brachial vein = post-axial limn.

Question 12

What are the markers of the pre and post-axial borders in the lower limb?

Answer 12

1. Saphenous vein = pre-axial.
2. Small saphenous vein = post-axial.

Question 13

What forms the plexus?

Answer 13

Anterior rami.

Question 14

What are the spinal nerves that enter the limb plexus like?

Answer 14

These come from enlarged parts of the cord - these are produced by the increased numbers of motor neurons in the anterior horns at these levels.

Question 15

What are the two types of skin maps?

Answer 15

1. Segmental innervation.
2. Peripheral nerves.

Question 16

Why are there two types of skin maps/charts?

Answer 16

1. One spinal nerve can contribute to multiple peripheral nerves.
2. One peripheral nerve can receive fibres from more than one spinal nerve.
   So some maps show the charts where the spinal cord supplies/area. Some maps show where a particular spinal nerve supplies.

Question 17

What are the divisions of the limb plexus?

Answer 17

1. Anterior.
2. Posterior.

Question 18

What does the anterior division of the limb plexus supply?

Answer 18

1. Flexor compartment - has a richer nerve supply (to both skin and muscle supplies).

Question 19

What does the posterior division of the limb plexus supply?

Answer 19

1. Extensor compartment of the limb.

Question 20

What is the tibial division of the sciatic nerve?

Answer 20

L4-5, S1-3.

Question 21

What is the perineal division of the sciatic nerve?

Answer 21

L4-5, S1-2.

Question 22

Can flexor muscles receive extensor nerve supply?

Answer 22

Yes - muscle developed in extensor compartment (so receives extensor nerve supply) however migrated to flexor compartment but it keeps its nerve supply.

Question 23

What is an example of a flexor compartment muscle receiving extensor compartment nerves?

Answer 23

Lateral portion of brachial is and short head of biceps femora’s.