It is knuckle
Those letters can be rearranged to spell knuckle.
The letters 'leukkcn' can be rearranged to spell the body part knuckle.
toenail
You can spell either bowel (internal) or elbow (external).
The missing letters, mtcahso, spell out "stomach" in reverse.
The letters spell the word thorax. It is a body part.
traches
The throat is the body part that has the letters "rathe" in it.
The letters spell the word liver. The liver is a body part.
The fallopian tubes is a body part that begins with the letter F and has 8 letters.
armpit
tummy!