Setup – Numb Thumb Median-Radial Sensory NCS

Electrode placement (use the ring electrodes)

• E1 (black):  Base of thumb
• E2 (red):  3-4cm distally from E1.
• Ground:  Dorsum of hand

Stimulation site

• Two sites
  • Radial nerve site
    • (-) Cathode (black):  10-cm proximal to E1, along the lateral forearm.
    • (+) Anode (red):  proximal (in line with the radial nerve)
  • Median nerve site
    • (-) Cathode (black):  10-cm proximal to E1.  Note: Make the 10-cm line to the middle of the wrist crease, then proximal along the median nerve.
    • (+) Anode (red):  proximal (in line with the median nerve)

Additional Information

• Type of stimulation = Antidromic
• One of the three studies for the combined sensory index (CSI): numb thumb, split ring, P8
• CPT codes for nerve conduction studies
  • 95900 Nerve conduction, amplitude and latency/velocity study, each nerve; motor, without F-wave study
  • 95903 Nerve conduction, amplitude and latency/velocity study, each nerve; motor with F-wave study
  • 95904 Nerve conduction, amplitude and latency/velocity study, each nerve; motor with F-wave study, each nerve; sensory
  • 95934 H-reflex, amplitude and latency study; record gastrocnemius/soleus muscle
  • 95936 Record muscle other than gastrocnemius/soleus muscle