I have often observed the knuckles of some people bearing weird bruises. Googling tells me a 'callus' fits the description of the bruise. Is there a term for these knuckles?
I don't know if there's a more appropriate one, but I'm partial to using the word gnarled in this situation. Especially when I want the aged, hard work or ruggedness connotations.
full of knots or gnarls : knotty [gnarled hands]
I found the term I was looking for: