Albert Barnes Commentary Psalms 102:5

"By reason of the voice of my groaning My bones cleave to my flesh." — Psalms 102:5 (ASV)

By reason of the voice of my groaning - By suffering and trouble, so great as to produce groaning, my flesh is wasted away.

My bones cleave to my skin - Margin, “flesh.” The Hebrew word means “flesh.” The effect described is that of a wasting away or an emaciation of flesh from deep distress, so that the bones became prominent and had nothing to hide them from view. As a result, they seemed to adhere fast to the flesh itself. See the notes on Job 19:20.