The role of an operating microscope in medico-legal practice

This article describes our experience in the use of a binocular surgical microscope at autopsy for the in situ forensic examination of various types of mechanical skin wounds. The microscopic image was visualised on a closed-circuit television monitor, and colour photographs and video recordings were simultaneously obtained from the monitor. With abrasions, small epidermal tags, which play a key role in the determination of external force direction, were clearly observed. With lacerations, crushing of the epidermis was observed at the wound margin, and continuous bridges of connective tissue and/or blood vessels were also found within the wound cavity. With incised wounds, the epidermis was intact up to the wound margin, and there was no continuous bridge within the wound cavity. Using these differences, it was, therefore, simple to distinguish lacerations from incised wounds. Ligature marks due to hanging were clearly observed, with petechial haemorrhages and minute abrasions readily seen in the lesion. For stab wounds caused by a single-edge knife, the morphological difference between the two ends of the wound caused by the sharp blade and the blunt side could be distinguished. It was also possible to confirm the identification of unknown cadavers by observing old wound scars using the operating microscope. Abnormal lesions of the blood vessels, such as a mechanical tear of the vertebral artery (the origin of a subarachnoid haemorrhage) and the atherosclerotic stenosis of the coronary artery, were detectable. In addition, the microscope was useful as a teaching aid to colleagues and medical students to study the nature of the wounds during or after the autopsy. We believe that this system presents advantages in terms of education and training of forensic pathologists and physicians as well as crime investigation officers.