Wrist drop finding
This patient with right wrist drop has weakness of wrist extension with preservation of finger flexion. Note, however, to obtain a true measure of finger flexor strength, it would have been best to first passively extend the wrist.
[Doctor] Sir, could you lift your wrist back for me? Okay, don’t let me move your hand. Good.”
[Doctor] The other hand, sir, can you lift your wrist back with this hand? That’s the best you can do, sir?”
[Patient] Yes.
[Doctor] Okay. Can you move, can you squeeze your fingers?
[Doctor] Okay. Thank you, sir.
About wrist drop
A wrist drop is due to weakness of wrist extensor muscles. In the typical presentation of wrist drop, the finger extensors are also weak and the finger flexors have normal strength. Note, however, that accurate assessment of finger flexor strength can only be made with the wrist passively extended to overcome the mechanical disadvantage that occurs when the wrist is flexed.
Localization
Wrist drop usually occurs due to a lesion of the radial nerve, most often due to compression of the nerve against the humerus during sleep. The condition is sometimes called “Saturday night palsy.” It may also occur in patients with a humeral fracture.