Radial nerve

Inspection:

• wrist drop
  
• wasting of 1st dorsal interossei
  
• scar over elbow

palpate:

• decrased sensation over 1st dorsal web space
• preservation of DIPJ extension (interossei and lumbricals - median and ulnar nerve)
  

differentiate level

• wrist
• only involve posterior interosseus nerve - sensation normal, only weakness
  
• humerus
• decrease sensation over forearm
  
• cervical
• decrease power of triceps