The skin is the heaviest organ in the human body, with the greatest surface area. Like other organs, it can be affected by numerous conditions which can be difficult to distinguish. Some skin lesions are purely imperfections, while others can be health risks. Dermatological surgery removes these lesions at their root, so they can be analysed under the microscope by an anatomical pathologist. Surgical incisions are made in such a way that the resulting scars are as invisible as possible. The defect that results from the removal of a large skin lesion sometimes cannot be closed by simply drawing the edges of the wound together. In these cases the defect can be repaired with skin grafts taken from other parts of the body that are similar for tissue type and look, or by rotation, sliding or translation of skin flaps from nearby areas.