if she is wearing a ring on the left thumb means she is married but available for sex

Indeed. My left thumb developed a deep bone bruise and resultant nerve damage to thumb tip. I was fanatical in my love of hitting and wore my aluminum bats out. However, those "dead bats" caused me to start having pain in my thumb,a burning and tingling sensation at age 14. I'm 35 now and my thumb still bothers me...

thumb nail, thumb tack, thumb screw, thumb print

My thumb, from the palm-thumb joint to the thumb-tip is 7.0 cm.