Nervous System - Nerve Supply of Limbs Flashcards
What are the three strips of the body wall?
- Longitudinal.
- Posterior.
- Ventral.
What supplies the longitudinal strip?
Posterior rami.
What supplies the lateral strip?
Lateral branches of the anterior rami.
What supplies the ventral strip?
Anterior terminal branches of anterior rami.
Where do limb buds grow from?
Lateral strip.
What do the lateral branches of the anterior rami form?
Anterior and posterior divisions of the lateral branches form - Plexuses for supply of the muscles and skin of the limbs.
What does the posterior division of the lateral branches of the anterior rami form?
Extensor muscles and skin of the limbs.
What does the anterior division of the lateral branches of the anterior rami form?
Flexor muscles and skin of the limbs.
Where do the flexor and extensor compartments meet?
Pre-axial and post-axial borders of the limb.
What marks the pre and post-axial borders of the limb?
Veins.
What are the markers of the pre and post-axial borders in the upper limb?
- Cephalon vein = pre-axial border.
- Brachial vein = post-axial limn.
What are the markers of the pre and post-axial borders in the lower limb?
- Saphenous vein = pre-axial.
- Small saphenous vein = post-axial.
What forms the plexus?
Anterior rami.
What are the spinal nerves that enter the limb plexus like?
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.
What are the two types of skin maps?
- Segmental innervation.
- Peripheral nerves.
Why are there two types of skin maps/charts?
- One spinal nerve can contribute to multiple peripheral nerves.
- 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.
What are the divisions of the limb plexus?
- Anterior.
- Posterior.
What does the anterior division of the limb plexus supply?
- Flexor compartment - has a richer nerve supply (to both skin and muscle supplies).
What does the posterior division of the limb plexus supply?
- Extensor compartment of the limb.
What is the tibial division of the sciatic nerve?
L4-5, S1-3.
What is the perineal division of the sciatic nerve?
L4-5, S1-2.
Can flexor muscles receive extensor nerve supply?
Yes - muscle developed in extensor compartment (so receives extensor nerve supply) however migrated to flexor compartment but it keeps its nerve supply.
What is an example of a flexor compartment muscle receiving extensor compartment nerves?
Lateral portion of brachial is and short head of biceps femora’s.