Ch. 12: Peripheral NS Flashcards
Peripheral Nerve
- distal axon projections
- After nerve leaves spinal canal
Cervical Plexus
- C1-C4
- motor, sensory, sympathetic to neck and tops of shoulders
Brachial Plexus
- C5-C8, T1
- Motor, sensory, sympathetic to arms
Sacral Plexus
- L4-S4
- motor, sensory and parasympathetic to back and bottom of legs
Damage to spinal nerve causes:
- minor weakness to 1+ muscles
- (b/c Mm are innervated by more than one spinal level)
-sensory loss in dermatomal pattern
Damage to Peripheral Nerve Causes:
- paralysis to 1+ Mm
- (b/c a muscle is only supplied by one peripheral nerve)
-sensory loss in peripheral pattern
Spinal Nerve at risk from:
- bulging disc
- collapse of intervetebral foramen
Lumbar Plexus
- L1-L4
- motor, sensory, sympathetic to front of legs
Principles of a plexus
- one peripheral nerve gets axons from many different spinal levels
- one spinal level sends axons to many different peripheral nerves
Spinal Nerve
- joining of one spinal level
- all sensory, motor and autonomic
- dividing line between central and peripheral NS
- dermatomal/myotomal pattern when damaged
Rami
- ventral
- dorsal
- communicating
Axon Connective Sheaths
- endoneurium
- perineurium
- epineurium
Nerves and movement
- nerves love blood, space and movement
- Movement increases blood flow, facilitates gliding of N, and axoplasmic transport
- nerve axons have wrinkling in endoneurium to allow movement
If nerves can’t move:
the axons stick to connective tissue and shorten
Dysfunction of peripheral Nn
- Sensory changes
- Motor changes
- Autonomic changes