Old drawing painting of a flayed man, 18th century anatomy

Old drawing painting of a flayed man anatomy 18th century. Subject: anatomy study, medicine. Support: graphite on laid paper. Dimensions with frame: 47.5 X 60.5 cm. Dimensions without frame: 29.4 X 42 cm. Condition: good general condition (see photos) Period: 18th century. Watermark to be deciphered.