Anatomy of Susceptible Sites for Nerve Damage

Susceptible Sites for Nerve Damage

• Abrupt neural branches, particularly in areas where the nerve's ability to move within surrounding structures is limited
• Examples: common plantar digital nerve in the web space between the third and fourth toes, common peroneal nerve as it traverses around the fibular head
• High-friction areas where nerves are close to unyielding interfaces
• Examples: nerves passing through the plantar fascia in the foot, brachial plexus passing over the first rib
• Tension points, such as the tibial nerve in the popliteal fossa, where abnormal stress can be placed on the nerve

Mechanosensitivity and Neuropathomechanics

• Nerve inflammation can lead to mechanosensitivity (sensitivity to mechanical stimuli such as joint movement)
• Mechanosensitivity can produce symptoms
• Differentiating between neuropathomechanics and neuropathophysiology:
  • Neuropathomechanics: no pain at rest, movement provokes pain, pain relief with rest
  • Neuropathophysiology: pain at rest, movement provokes severe pain, pain persists after rest

Detecting Mechanosensitive Areas

• Palpation: palpating different areas of the nerve to detect mechanosensitivity
• Special tests: ULTT, SLR, Slump test, etc.
• Palpation should be done at least at 2 sites to confirm mechanosensitivity of neural tissue

Basis of Symptoms

• Blood supply to the nervous system
• Axonal transport in the nervous system
• Innervation of connective tissues in the nervous system
• Lattice collagen arrangement in the nervous system

Lattice Collagen Arrangement

• Elongation of the cord stretches longitudinally running vessels and folds transversely running vessels
• Veins in the spinal canal are valveless and allow flow reversibility
• Critical vascular zone from T4 to T9
• Arrest of blood flow at 8% elongation, complete arrest at 15% elongation

Axonal Transport System

• Three flows identified: anterograde flow, retrograde flow, and bidirectional flow
• Flow interruption induces cell body reaction
• Constriction, loss of blood supply, and viruses may impede the flow

Innervation of Nervous System

• Innervation of connective tissues in the nervous system
• Dura mater innervated by segmental, bilateral, and sinuvertebral nerves
• Innervation density varies depending on spinal segment
• Rich innervation in superficial tissues, less in deeper tissues

Clinical Neurobiomechanics

• Mechanical properties of neural tissue: sensitive but not delicate
• Palpation of difficult areas:
  • Apply pressure at the carpal tunnel for 30 seconds with 4.5 kg pressure to detect median nerve injury

Neurodynamics as a 3-Part System

• Mechanical interface: the container for the nervous system
• Neural structures: brain, spinal cord, nerve roots, neural plexuses, peripheral nerves, and their connective tissues
• Innervated tissues: connective tissues of the nervous system