The Humby dermatome is a surgical instrument used to harvest skin grafts for reconstructive procedures. It’s a manual dermatome, specifically a type of skin graft knife, that allows for adjustable thickness of the skin slice taken from a donor site. The instrument features a roller and a blade, with the distance between them adjustable to control the thickness of the graft. This allows surgeons to precisely control the depth of the skin graft, which is crucial for successful transplantation.