Neurodynamics Flashcards
Fun Facts
Spinal cord length is 7-10cm longer in flexion than extension
the median nerve must adapt to be 20% longer w/ wrist & elbow flex/ext
Common Tension Points
C6, T6, L4, Posterior knee & Anterior elbow
T6 is MOST COMMON
Axoplasm
axoplasm = nerve cytoplasm
“transport system” w/n the nerve that carrys cell components to and from cell bodies and terminal ends
Axoplasm is thixotropic - meaning it is movement and circulation dependent so if you are immobilized your axoplasm is not moving either
Nerves & Blood
Demands 25% of cardiac output
NS accounts for 7% of body weight
The peripheral nerve can be elongated 8%, after this point the blood circulation is cut off and there can be possible damage to the nerve
Pain Generators (7)
blood flow (ischemia), axoplasmic flow (immobilization/ischemia), double crush, connective tissue, Abnormal impuse generating sites(AIGS), Substance P and surrounding tissue injury
Inflammation and ischemia are main causes of neural symptoms
Blood Flow - ischemic nerve injury
minor compression (30mmHg) can cause ischemia
edematous stage will occur if venous flow restriction is held long enough
Resulting in a swollen and painful nerve
Immobilization - effects on axoplasm & nerve
axoplasm moves up to 100-400mm/day
if there is no motion or ischemia the flow will slow or even stop
Immobilization:
3 weeks –> degenerative changes in myelin
6 weeks –> collagen deposition in th eendoneurium
6-16 weeks –> decrease fiber diameter of myelinated fibers
Double Crush
when injury to one area of the nerve can lead to pathology in other sites of the nerve
Double crush = symptoms DISTAL to the site of injury
(hit your funny bone and you feel it in your hand)
Reverse double crush = symptoms PROXIMAL to the site of injury
Connective tissue
connective tissue is highly innervated w/ free nerve endings and Pacinian corpuscles (pressure sensors)
surrounded by unmyelinated fibers containing pain neuropeptides
Connective tissue is 50% of diameter of nerve, so major source of pain generator
Abnormal Impulse Generating Sites (AIGS)
vascular injury to the axon can cause ion channels to get stuck in the axolemma and begin to fire
when the axoplasm stops moving due to ischemia, the ion channels will remain open creating a persistent issue
the pain is DIRECTLY coming from nerve signals, no underlying tissue injury
SYMPTOMS: n/t, temperature or pressure changes
TREATMENT: movement!
Substance P
- normal vs. abnormal pain process
NORMAL - stimulus followed by descending inhibition
- Glial cells quiet, normal amt of substance P released
ABNORMAL - no inhibition from descending pathways
- glial cells activated releasing inflammatory chemicals which increases substance P
–> this response is common in fibromyalgia patients
Surrounding tissue injury
can cause nerve injury due to swelling in the area of the injury
May require immobilization
Two ways to test neural tension:
- Palpation
- Neural Tension testing
- placing the nerve on tension w/ different movement techniques
Positive findings = comparable sign, asymmetrical ROM, change of sensation in the distribution of the nerve being tested
Sliders vs. Tensioners
Sliders = flossing the nerve through the surrounding tissue w/o tensing the entire length of the nerve
- acute injury or very irritable symptoms
- i.e. elbow flexion –> extension
Tensioners = tensioning of the entire length of the nerve
- chronic injury or low irritability
- i.e. SLR w/ IR and adduction
Principles of Neural Tension Treatment (3)
- LOW INTENSITY
- allows for fluid movement
- in PAIN FREE range, stop before any symptoms - LOW DURATION
- 1 second duration to allow for blood flow - HIGH REPETITIONS
- 25-50 repetitions, 3-5x/day
- start lower and work up tolerance