US Patent 8216265 Medical instrument for punching out tissue

Medical instrument serves to punch out tissue. It has a shaft, a first cap-shaped tool arranged at a distal end of said shaft and having a circular cutting edge. A second tool has a circular cutting edge at a distal end thereof. Said first and said second tool can be shifted relative to one another along said shaft thereby that second tool can enter into the cavity of that first tool. Said second tool bears a plate-like element, distally spaced apart from its cutting edge, said plate-like element has an extension in a cross-section plane corresponding to a clear internal cross-section plane of said cavity.