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
Straight Leg Raise (SLR)
Perform test passively, watch for posterior pelvic tilt or stop when symptoms arise
Positive test = comparable symptoms, asymmetrical ROM, change in tissue tension when compared to unaffected side
0-30deg –> sciatic nerve
- due to large disc herniation and nerve tension
- educate about CE syndrome
30-70deg –> lumbosacral nerve roots (L4 - S2)
- to check if neural, slack, then DF the ankle
Anything beyond this would be hamstring or soft tissue
Neural testing candidates
nerve root compression nerve root tension disc herniation radiating symptoms instability --> leading to compression
Added Components to SLR
Dorsiflexion = tibial nerve
Dorsiflexion + inversion = sural nerve
Plantarflexion + infersion = peroneals
Hip adduction = lumbosacral plexus
IR = lumbosacral plexus
Difference between Slump test and SLR
- Slump is more aggressive (perform last)
- can also pick up anything in the thoracic spine (disc herniations/nerve root compression)
- puts more tension on the dura mater
Method of the Slump Test
- Patient slumps, apply OP to bow the spine
- Ask patient to take chin to chest, apply OP to CS
- Extend knee
- Dorsiflex
Positive test - symptoms must change w/ neck and foot motion
- if only changes w/ foot motion then most likely a lower nerve issue (local) and would not be a positive slump test
Prone Knee Bend (PKB)
indication: upper lumbar radiculopathy, anterior thigh/hip/knee pain
puts tension on femoral nerve and L2-L4 nerve roots
Is it tightness in the quads or tension on femoral nerve
- must compare to the other side
- reproduction of symptoms w/n 80-100 degrees of motion (that would be a really tight quad)
PKB/Slump
slump test for the femoral nerve (in side-lying)
- patient lies on side in trunk & neck flexion
- patient draws lower leg in and pull knee to chest
- examiner places top foot on their hip and flexes knee (plus hip extension)
must confirm findings w/ head and neck flexion and extension and knee flexion and extension
good test for differentiating nervous system involvement from non-nervous system structures
Slump test in Long-sitting
for people who are extremely flexible or if low disc issue to really wind up the lower NS first
- tension in nerves in LE and lower trunk is taken up first
allows for better assessment of thoracic and cervical movements in sitting
- patient is long sitting
- trunk flexion + OP and neck flexion + OP
Confirm findings w/ neck flex/ext
May add foot DF as well
Median Nerve Testing
Shoulder abduction +
Elbow extension +
Shoulder ER & supination +
Wrist & finger extension
