What does the description of McMurphy's hands suggest to the reader about his character in One Flew Over the Cuckoo's Nest?

I remember
the real clear way that that hand looked: there was carbon under the fingernails where
he'd worked once in a garage; there was a dirty Band-Aid on the middle knuckle, peeling
up at the edge. All the rest of the knuckles were covered with scars and cuts, old and
new. I remember the palm was smooth and hard as bone from hefting the wooden handles of
axes and hoes, not the hand you'd think could deal cards. The palm was callused, and the
calluses were cracked, and dirt was worked in the cracks. A road map of his travels up
and down the West. That palm made a scuffing sound against my
hand.

Early in the novel,
Kesey describes McMurphy's hands in order to characterize him. Although he is only
describing one physical aspect of McMurphy, his hands encompass every aspect of his
personality. He is a tough man whose life experiences have made him calloused and
scarred, not only on his hands, but also inside. Kesey is letting us know that he is
"thick-skinned"; he will be able to take a lot from Nurse Ratched and remain unphased.
Furthermore, the scars, cuts, and dirt suggest McMurphy is a fighter--one who is not
afraid to "get his hands dirty", literally and figuratively. McMurphy's strength and
resilience, which is going to help the patients find themselves, is symbolically
represented in his hands.