Whammy Vein

First coined by guitarist Thomas Corin, the "Whammy Vein" is the vein on the back of a guitarist's hand that is slightly more vascular than the rest.
This protrusion is caused by excessive use of the Whammy Bar.

Wow bro, I see you've been practicing your lead a lot lately, that Whammy Vein is starting to look like Mount Everest!