Occasionally, patients who have had a severe brain injury but recovered relatively quickly may present with complaints of odd nail discoloration. This may involve fingernails and/or toenails. What gives?

This is actually a byproduct of repeated exams to determine the Glasgow Coma Scale score. A common way to determine the motor component is to squeeze the fingertip or toetip. I’ve seen some neurosurgeons use a pen to apply a great deal of force to the nail.

The discoloration is a resolving subungual hematoma. You may see different colors under different nails, depending on the age of the hematoma. Amaze your colleagues with your knowledge on this one!