A biopsy device, comprising: a first cannula having a first side wall defining a first lumen, said first cannula having a first proximal end and a first distal end, said first cannula having a first aperture extending through said first side wall to said first lumen proximal to said first distal end, said first cannula having a longitudinal axis; a second cannula having a second side wall defining a second lumen, said second cannula having a second proximal end and a second distal end, said second cannula having a second aperture extending through said second side wall to said second lumen proximal to said second distal end, said second cannula being disposed co-axially with said first cannula, at least one of said first aperture and said second aperture having a cutting edge; and a driver unit having a ratchet drive mechanism operatively coupled to said first cannula and said second cannula, said ratchet drive mechanism including: a first gear fixedly attached to said first cannula; a second gear fixedly attached to said second cannula; and a torsion spring located between said first gear and said second gear, said torsion spring having a first end portion and a second end portion, said first end portion being connected to said first gear and said second end portion being connected to said second gear, said ratchet drive mechanism being configured such that said torsion spring stores energy which when released drivably rotates one of said first gear and said second gear relative to the other of said first gear and said second gear. a first cannula having a first side wall defining a first lumen, said first cannula having a first proximal end and a first distal end, said first cannula having a first aperture extending through said first side wall to said first lumen proximal to said first distal end, said first cannula having a longitudinal axis; a second cannula having a second side wall defining a second lumen, said second cannula having a second proximal end and a second distal end, said second cannula having a second aperture extending through said second side wall to said second lumen proximal to said second distal end, said second cannula being disposed co-axially with said first cannula, at least one of said first aperture and said second aperture having a cutting edge; and a driver unit having a ratchet drive mechanism operatively coupled to said first cannula and said second cannula, said ratchet drive mechanism including: a first gear fixedly attached to said first cannula; a second gear fixedly attached to said second cannula; and a torsion spring located between said first gear and said second gear, said torsion spring having a first end portion and a second end portion, said first end portion being connected to said first gear and said second end portion being connected to said second gear, said ratchet drive mechanism being configured such that said torsion spring stores energy which when released drivably rotates one of said first gear and said second gear relative to the other of said first gear and said second gear. a first gear fixedly attached to said first cannula; a second gear fixedly attached to said second cannula; and a torsion spring located between said first gear and said second gear, said torsion spring having a first end portion and a second end portion, said first end portion being connected to said first gear and said second end portion being connected to said second gear, said ratchet drive mechanism being configured such that said torsion spring stores energy which when released drivably rotates one of said first gear and said second gear relative to the other of said first gear and said second gear.