A biopsy apparatus includes a housing, a biopsy cannula mounted to the housing, and a cannula rotation mechanism mounted to the housing. The cannula rotation mechanism has a thumbwheel, a first gear, and a second gear. The thumbwheel is configured to rotate about a rotational axis, with the rotational axis being perpendicular to the longitudinal axis of the biopsy cannula. The first gear is mounted in fixed attachment to the thumbwheel. The second gear is mounted in fixed attachment to the biopsy cannula. The first gear is in mesh with the second gear such that the first gear is directly drivably engaged with the second gear to rotate the biopsy cannula about the longitudinal axis when the thumbwheel is rotated.