expression
skin and bones; nothing but skin and bones
A humorous, somewhat dated phrase describing someone extremely thin. Often used in a self-deprecating or joking manner.
病気で入院していたら、骨皮筋右衛門になってしまった。
After being hospitalized with an illness, I ended up nothing but skin and bones.
The exact origin is uncertain. It appears to be a playful Edo-period coinage combining 骨 (bone), 皮 (skin), 筋 (sinew), and the common male name suffix 右衛門, humorously personifying extreme thinness.