Neural Mobilization Exam + Intervention Flashcards
Current State of evidence for efficacy of neural mobilization
Ellis et al.
Basson et al.
see pics
Neural Structure
2 Main Types of Tissue:
- Impulse gen. and conduction
- axons, myelin, Schwann cells
- those assoc’d w/ support and protection of the impulse conducting tissues
- neuroglia, Schwann cells, connect. tissue layers
Connective tissue relationships exist from _____ TO _____
from axon TO neuraxis
Approx 50% of the P. nerve is connective tissue sheath
Some stats..
- Ulnar N. @ elbow= 21%
- Sciatic N. @ buttocks= 81%
4 Major tissue layers in and around the P. nerve
Starting from the axon (innermost) and working to exterior of the nerve
- Endoneurium
- Perineurium
- Epineurium
- Mesoneurium
Endoneurium
“Inner-most” layer
- Surrounds neuron
- HIGHLY elastic→ made of close packed collagen tissue
- Contains endoneurial fluid under positive pressure
- *responsible for maint. healthy environment of axon
- Blood-Nerve Barrier***
-
Contains NO LYMPHATICS
- if swells– cannot drain
Perineurium
Endoneurium→ Perineurium
- Surrounds Fascicles (bundles of endoneurium)
- Multi-layered→ most collagen fibers running parallel to nerve fiber
- HIGHLY resistant to tensile forces
- Acts as BOTH mechanical barrier to mech. forces and a diffusion barrier to keep substances OUT of intrafascicular environment
-
Contains NO LYMPHATICS
- if swells→ cannot be drained
Epineurium
Endoneurium→ Perineurium→ Epineurium
Outer vs. Inner
-
Outer Epineurium
- contains vascular comps→ lymphatics AND blood supply
-
Internal Epineurium
- surrounds and protects fascicles from ext. trauma
- allows for interfascicular gliding
Mesoneurium
Endoneurium→ Perineurium→ Epineurium→ Mesoneurium
- Forms loose connect. tissue sheath around nerve
- Facilitates nerve gliding of AND anchors nerve in the nerve bed
- *W/ injury→ often becomes fibrotic and shrinks to constrict nerve and forms adhesions to the nerve bed
Nerve Root Complex
Components of this:
- Dorsal and Ventral Roots
- Dorsal Root Ganglion (DRG)
Nerve Root Complex
Dorsal and Ventral Roots
- RARELY damaged from traction force 2* to protective and force distributive mechs.
- i.e. denticulate ligs
- receive @ least 50% nutrition from CSF
Nerve Root Complex
Dorsal Root Ganglion (DRG)
- Normally minimally mechanosensitive
- poke, prod== no response
- Once irritated→ very mechanosensitive
- MAY become edamatous
- This cond. is hypothesized to improve via pumping action w/ mvmt
Connective Tissue Relationships:
P. nerves to Neuraxis
What are they continuous with?
- Epineurium continuos w/ Dura Mater
- Perineurium MOSTLY cont. w/ dura, portion cont’s as Pia mater
- Endoneurium cont. w/ Pia mater
The Meninges
3: Inner→ Outermost
- Dura mater
- Arachnoid mater (spider-web like)
- Pia mater
The Meninges:
Dura mater
- Strong longitudinally→ mostly collagen fibers in long. orientation
- Elastic as well*→ Elastin content varies 7% ventral to 14% dorsal
The Meninges:
Arachnoid mater
- Delicate mesh (spider-web) of collagen fibers in random orientation
- Lines inside of dura
The Meninges:
Pia mater
- Another collagen mesh-like structure
- Lines outer surface of brain & SC
The Meninges:
Pia + Arachnoid mater TOGETHER→
Leptomeninges
- Embryologically ONCE one memb.
- Interconnections (trabeculae) b/w the two dampen CSF pressure waves from mvmt.
The Meninges:
As a Muscle Attachment.. explain
- Evidence of MYO-dural (muscle→ dura) connections b/w suboccipital mm’s
- Rectus capitis post. minor
- Rectus capitis post. major
- Obliquus capitis inf.
The Meninges:
As a Muscle Attachment.. explain
Myodural Connections
Explain further: what does it DO?
- MAY assist in checking dural in-folding and impinge. during C/S Ext.
- Feedback function→ rich in proprioceptors
- Maint. proper dural tension to facilitate CSF dynamics
- MAY play a role in cervicogenic HA’s
Potential for Nerve Injury:
Space + Contents Dilemma
- Nerve passes thru several tight anatomical comps along course of nerve bed
-
Conflicts arise b/w avail. space and contents
- diminished compartment aperture
- INCd volume of contents
- RESULT:
- restricted gliding b/w tissues in compartment
- interrupted nerve physio.
- impaired blood supply
Circulation of the NS
Blood Supply to nerve
What is this called?
Vasa Nervorum
Explain the Circulation of the NS
Vasa Nervorum
*Great redundancy!!!
- Neural tissue is O2 HUNGRY!!!
- 2-6% of body mass but utilizes 20% of avail O2
-
Redundant Design*
- ensures uninterrupted blood flow to neurons regardless of mvmt or static pos. of NS
- Stretch and compression CAN alter circulation
- hypoxia, edema, then fibrous changes in the nerve can follow chronic interruption in blood flow
Axonal Transport Systems
Explain..
- Mvmt of mitochondria, lipids, synaptic vesicles, PROs, prions, organelles thru the cell’s axoplasm TO and FROM neurons Cell Body
- Active→ HIGH energy demand process
- Mvmt along microtubules acting as train tracks
- Kinesin and dynein motor PROs move cargo along microtubules
Axonal Transport Systems:
Fast and Slow Transport
-
FAST (50-400mm/day)
- analogous to taking the express train
-
SLOW (.1-6mm/day)
- analogous to taking the local train w/ lots of steps along the way
Axonal Transport Systems:
Anterograde Transport
AWAY from cell body (soma)
-
FAST→ responsible to transport of neurotransmitter vesicles
- 400mm/day
-
SLOW→ resp. for transport of cell building materials
- microtubules and neurofilaments→ .1-1mm/day
- Actin→ 2-3mm/day
- ~200 other PROs @ speeds up to 6mm/day
Axonal Transport Systems:
Anterograde Transport
AWAY from cell body
Example:
- During reactivation from latency, herpes simplex virus (HSV) hitches ride on the anterograde transport mechs to migrate from DRG neurons TO the skin or mucosa affected****
Axonal Transport Systems:
Retrograde Transport
TOWARDS the cell body (soma)
- Returns used synaptic vesicles TO SOMA (cell body)
- Informs soma of cond’s @ the axon terminals
- Exploited by pathogens as well
-
delay b/w infection and disease expression==> travel time TO SOMA
- HSV
- Rabies
- Polio
-
delay b/w infection and disease expression==> travel time TO SOMA
Axonal Transport Systems:
Kinesin Motor PROs
- Utilizes ATP→ ADP as energy source***
- 125,000 steps= 1mm dist. traveled along microtubule—–WOW!!!
Axonal Transport Systems:
Consequences of disruption of axonal transport system
- Inflamm. of the nerve
- Loss of nerve function
- Nerve becomes “sick”
Neural Response to Injury:
Mild, focal compression
- Injury to Schwann cell
- Demyelination results
Neural Response to Injury:
More severe trauma
- Degen. of the distal axon
- Reactive changes to nerve cell body
- aka Wallerian Degeneration
- NOTE: recovery NOT possible w/out Sx
Neural Response to Injury:
Injury w/out axonal degeneration
- Inflamm in and around nerve sheath
- Activates C and A delta fibers
-
Nervi Nervorum (nerve→nerve) involved:
- innervates connect. tissue and blood vessels of the NS
Neural Response to Injury:
EMG and NCV Testing
*NVC=Nerve Conduction Velocity
- **ONLY valuable for detecting larger diameter A-beta sensory & motor nerve injury
- “A-beta’s make it betta”
-
***Of no value for detecting small diameter nerve injury
- C and A-delta fibers, Nervi Nervorum
How do we ID Pts w/ Nerve Injury W/OUT axonal degen?
- Nerve tissue becomes mechanically sensitized (C and A delta fibers via nervi nervorum) in reaction to interruption of axonal transport and inflammation in or around nerve
- Sensitized neural tissue responded to as little as 3% stretch→ well w/in normal mvmt parameters
- Sensitized neural tissue now reacts to stretch and pressure
*NOTE: These principles form the physiologic basis for Neurodynamic Testing!!!
Key Takeaways from Neurodynamic Testing:
- Vast # of nerve injuries not detected via EMG/NCV
- Neural sensitization involves injury to small diameter A-delta and C fibers of the nerve AND nervi nervorum
- Occurs thru inflammation and interruption of axonal transport system
- *Inflamm+Axon Neural Transport very intimately related
- when you compress nerve→ becomes pro-inflammatory
- In the Clinic..
- detected via palpation and stretch on clinical exam
- aka how to detect injured neural tissue
- detected via palpation and stretch on clinical exam
Neural Mobility Testing
Indications
- Pain/parasthesia of neural origin deduced via exam and hx
- Limtd mobility of NS
- Injury of tissue close to nerve beds
- whiplash
- HS injury
- Sciatic N.
- Lat. Epicondylalgia
- Radial Nerve
- Medial Epicondylalgia
- Ulnar N.
- Ankle sprain
- Sural and Superficial Peroneal N branches
- Suspected cervical radiculo.
- part of test item cluster to ID this patho
- Post-op spine pts
Neural Mobility Testing
Contraindications
- Acute inflammatory infection involving SC or NS
- Acute/recent onset of hard neuro. signs
- loss of reflexes
- localized mm weakness
Neural Mobility Testing
Precautions
- Malignancy
- Be aware of stress to anatomical structures during testing
- Slump: HNP concerns, nerve root impinge signs
- Irritability lvl of the pts NS
- Presence of stable hard neuro signs
- Gen health issues:
- IDDM/NIDDM, RA, MS, etc..
- Circulatory disorders
Structural Differentiation w/ Neural Mobility
Key Concepts
- always skip an articulation (jt complex) from where sx’s are produced or changed during baseline tests
- Add/Subtract tension to look for corresponding change in sx’s
- Symptoms typ worsen w/ tension add→ but not always
Meralgia Parasthetica assoc’d w/
LFCN entrapment
Meralgia Parasthetica
Irritation or entrapment of LFCN @ anterolateral hip
@ risk= baseball catchers, equestrians (Eng-style), obese indvs, pregnant women, ant. approach THA and hip arthroscopy pts)
Test for Meralgia Parasthetica
push w/ thumb down into abdomen and up toward umbilicus @ lvl just proximal to and 1” medial to ASIS.
If this relieves pts sx’s of lat. thigh burning, pain, or parasthesia→ suggests meralgia parasthetica is problem
To treat→ apply same pressure to the nerve w/ pt in S/L, while you simultaneously passively extend hip
*push down and up on nerve as you ext hip, then move back and forth
