nerve conduction sompol tapechum m.d., ph.d. department of physiology
DESCRIPTION
Objectives นักศึกษาสามารถบอกประโยชน์ของการวัด nerve conduction velocity ได้ นักศึกษาสามารถบอกวิธีการวัด nerve conduction velocity ได้ นักศึกษาสามารถบอกปัจจัยที่มีผลต่อ nerve conduction velocity ของ axon ได้TRANSCRIPT
Nerve conduction Sompol Tapechum M.D., Ph.D. Department of
Physiology
Faculty of Medicine Siriraj Hospital Objectives nerve conduction
velocity nerve conduction velocity nerve conduction velocity axon
Nervous system Structure of Nervous system
Central nervous system (CNS) Brain Cerebrum Cerebellum Brainstem
Spinal cord Peripheral nervous system (PNS) Nerves Cranial nerve 12
pairs Spinal nerve 31 pairs Spinal nerve and Cranial nerve Nerve
structure Nerve = Bundle of axon Component of nerve Motor
Somatic Autonomic Sensory Visceral Axon Motor neurons Sensory
neurons Orthodromic Antidromic Orthodromic Types of axon Type of
axon Information Processed
Table I Somatosensory Receptors and their Peripheral Axons Receptor
Type Axon3 Group CAP Peak Conduction Velocity Axon Diameter
Information Processed Muscle Spindle: Annulospiral endings Ia Aa
m/sec mM Muscle length and velocity Muscle Spindle: Flower Spray
endings II Ab m/sec mM Muscle length Golgi Tendon Organ Ib Muscle
tension Joint: Pacinian Joint movement Joint: Ruffini Joint angle
Joint: Golgi Tendon Organ Joint torque Meissner corpuscle Touch,
flutter or movement Pacinian corpuscle Vibration Ruffini corpuscle
Skin stretch Hair follicle II & III Ab & Ad m/sec 2 -12 mM
Touch movement Merkel complex Fine touch Free Nerve Endings III Ad
m/sec 1 - 6 mM Sharp pain or cool/cold IV C m/sec < 1.5 mM Dull
or aching pain, or touch or warm Nerve conduction Sensory
conduction study
Antidromic Sensory conduction study
Orthodromic Motor conduction study
Orthodromic Median nerve Motor conduction study: Median nerve Motor
neuron Neuromuscular junction Neuromuscular junction Nerve
conduction velocity
NCV = D1-D2 L1-L2 D1 Latency (s)L1 L2 Sensory conduction study:
Median nerve Purposes of Nerve conduction study
To diagnose nerve damage or destruction To follow up nerve
regeneration after damage To evaluate diseases of nerve or muscle
Normal nerve conduction velocity
normal conduction velocity approximately 50 to 60 meters per
second. may vary from one individual to another and from one nerve
to another. Carpal tunnel syndrome Nerve injury Axon regeneration
2-4 mm/day Myasthenia gravis