1. Nerve conduction Sompol Tapechum M.D., Ph.D. Department of Physiology
Faculty of Medicine Siriraj Hospital

2. Objectives
นักศึกษาสามารถบอกประโยชน์ของการวัด nerve conduction velocity ได้
นักศึกษาสามารถบอกวิธีการวัด nerve conduction velocity ได้
นักศึกษาสามารถบอกปัจจัยที่มีผลต่อ nerve conduction velocity ของ axon ได้

3. Nervous system

4. 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

5. Spinal nerve and Cranial nerve

6. Nerve structure Nerve = Bundle of axon Component of nerve Motor
Somatic
Autonomic
Sensory
Visceral

7. Axon Motor neurons Sensory neurons Orthodromic Antidromic Orthodromic

8. Types of axon

9. Type of axon

10. 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

11. Nerve conduction

12. Sensory conduction study
Antidromic

13. Sensory conduction study
Orthodromic

14. Motor conduction study
Orthodromic

15. Median nerve

16. Motor conduction study: Median nerve

17. Motor neuron
Neuromuscular
junction

18. Neuromuscular junction

19. Nerve conduction velocity
NCV =
D1-D2
L1-L2 D1
Latency (s) L1 L2

20. Sensory conduction study: Median nerve

21. 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

22. 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.

23. Carpal tunnel syndrome

24. Nerve injury

25. Axon regeneration
2-4 mm/day

26. Myasthenia gravis