Adverse Neurodynamics Flashcards
Name some indications that pathology may include peripheral nerve involvement.
i) pain is radiating/radiculopathy
ii) positionall (“spontaneous”) and common movement aggravators
iii) burning, numbness, shooting quality
iv) neurofatiguable weakness
v) sensory changes
Explain what is meant by the term mechanosensitivity.
When exposed to mechanical stresses, periperal nerves increase in mechanosensitivity. This means symptoms are easier to reproduce (lower threshold) when the nerve is under the same stresses.
List three mechanical stresses that can produce symptoms in a peripheral nerve.
i) tension
ii) compression
iii) friction
Explain what a mechanical interface is with regard to neurodynamics.
Areas where nerves contact other structures. In these areas they can be compressed by these structures or tethered to them. Ex. flexor retinaculum and median nerve, fibular head and common peroneal nerve.
List the three membranous layers of a peripheral nerve in order from superficial to deep.
i) epineurium (separates fascicles)
ii) perineurium (surrounds fascicles)
iii) endoneurium (separates fibres)
Name three key identifiers of the epineurium.
i) facilitates gliding between fascicles
ii) consist of longitudinally aligned collagen
iii) highly reactive to injury
Name three key identifiers of the perineurium
i) consists of collagen and elastin
ii) diffusion barrier
iii) mechanical barrier to external forces
Name two key identifiers of the endoneurium.
i) consists of collagen
ii) maintains environment around nerve fibre (requires positive pressure!)
What factors contribute to variation of clinical presentation in peripheral nerve pathology.
i) vascular considerations (pressure gradient)
ii) mechanical considerations (friction, compression etc.)
iii) influence on axoplasmic flow
iv) extent of fibrosis
Describe the pressure gradient between a peripheral nerve and the nerve bed (surrounds nerve fibre).
P artery > P nerve fibre > P vein > P nerve bed.
Note: changes affect nutrition and nerve health.
What are the adverse effects of altered axonoplasmic flow in a peripheral nerve?
i) change in action potential (mechanosensitivity)
ii) altered structural integrity of axon and cell body
iii) trophic changes in target tissue (ex. skin/nails)
iv) compromised nerve conduction
What is necessary for normal axonoplasmic flow in a peripheral nerve?
i) adequate blood flow
ii) energy to consume
At which sites can fibrosis occur in peripheral nerve pathology?
i) between collagen fibres of a layer
ii) between membranous layers (ex. epineurium)
Explain the consequences of peripheral nerve fibrosis.
There will be decreased neural mobility in that area which will affect the neurodynamics of that nerve at other sites.
What is the distinction between an intraneural and extraneural pathology?
Extraneural pathologies involve the epineurium (ex. tethering to surround structures). Intraneural pathologies Intraneural pathologies involve structures within the nerve (ex. demyelination, neuroma).