Abstract: Surgical knife with controllably extendable blade, the blade retained by a blade holder extending through an axial opening in the knife body and connected with a member threadedly retained within the knife body for axial adjustment and also connected to an adjustment knob at the rear end of the knife. Another feature of the knife is a foot configuration which facilitates precise use and control of the knife. Preferably the invention also comprises the knife, as disclosed, in combination with a gauge for visually inspecting blade projection, the gauge indicator consisting of a pair of eccentric circles or portions thereof, the blade projection being measured by comparison with the radial distance between the two circles.

Abstract: Surgical knife with controllably extendable blade, the blade retained by a blade holder extending through an axial opening in the knife body and connected with a member threadedly retained within the knife body for axial adjustment and also connected to an adjustment knob at the rear end of the knife. Another feature of the knife is a foot configuration which facilitates precise use and control of the knife. Preferably the invention also comprises the knife, as disclosed, in combination with a gauge for visually inspecting blade projection, the gauge indicator consisting of a pair of eccentric circles or portions thereof, the blade projection being measured by comparison with the radial distance between the two circles.