Week 1: Intro, Bell's Palsy Flashcards
PNS
All neural structures outside the brain and spinal cord.
Sensory receptors, peripheral nerves, ganglia, efferent motor endings.
Nerve
Parallel bundles of peripheral axons enclosed by successive wrappings of connective tissue:
Endoneurium
Perineurium
Epineurium
Endoneurium
In a spinal or cranial nerve, the innermost layers of tissue surrounding an individual axon.
Perineurium
Intermediate (and thickest) layer of connective tissue in a spinal/cranial nerve. Covers fascicle.
Fascicle.
A bundle of endoneurium-wrapped axons, itself wrapped in perineurium.
Epineurium
Most superficial layer of connective tissue covering spinal/cranial nerves. Fibroblasts and thick collagen fibres.
Encases bundles of fascicles (ie the entire nerve).
Where the blood supply is.
Peripheral Nerves are classified as either:
Cranial or spinal
Ganglia
Collection of neuron cell bodies in the PNS.
The Cranial Nerves
I. Olfactory II. Optic III. Occulomotor IV. Trochlear V. Trigeminal VI. Abucens VII. Facial VIII. Vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII. Hypoglossal
Somatic Nervous System
Innervates all sensory organs, and voluntary muscles.
Nervus nervorum
The nerve’s nerve
Neuropathology
Study of diseases of the nervous system. Anatomic .
Neuropathy
Functional disturbance and/or pathological change in PNS. Typically causes numbness and/or weakness.
Neuralgia
Pain along the course of a nerve often in absence of objective signs
Neuritis
Inflammation of one or more nerves
Radiculopathy/Radiculitis
Damage to nerve root
Often results in pain along dermatome
Polyradiculopathy
Radiculopathy involving more than one nerve root
Causalgia
Peripheral nerve injury that causes severe SNS hyperactivity. (CRPS Type II)
Hyperalgesia
Sustained burning pain after nerve injury.
Should resolve after injury does.
Wallerian Degeneration
Demyelination and degeneration of axon distal to injury.
Neurolemma remains, Schwann cells multiply and form a regeneration tube, which guides the growth of a new axon.
Neuropraxia
1st degree damage
Transient conduction block
Local demyelination
Can affect either motor or sensory, but usually not both
Axonotmesis
2nd degree damage from prolonged, severe compression
Endoneural tube intact
Wallerian degeneration
Massage can help increase healing and maintain tissue health
Neurotmesis
Severance of nerve
Endoneural tube severed.
Sensory, motor and autonomic losses
Poor prognosis
Nerve lesions can be:
Complete or partial
Permanent or regenerating
Free Coaptation
Surgical procedure
Graft nerve without undue tension
When treating, be cognizant of new nerve position
Segmental Demyelination
Local damage to the myelin sheath. Often from (or synonymous with, or characteristic of) neuropraxia Axon remains intact; remyelination and recovery occurs
Polyneuropathy
AKA polyneuritis
Widespread degeneration of peripheral nerves. Often symmetrical
Classically:
- symmetrical weakness
- symmetrical distal sensory symptoms (ie stocking and glove)
- hyporeflexia (esp with DM, leprosy, infections, Vit B deficiency)
Motor Neuropathy
Weakness, flaccid paralysis, atrophy, decreased DTR’s
Ex. Guillain-Barre syndrome