Medicinal needle containing spring-loaded guard

摘要

The distal end of the tubular needle is chamfered to form a sharp point, and inside it is a tubular coaxial guard (14) movable rearwards against spring action. The guard distal end is closed by a blunt transparent surface, and in the forward position it protrudes beyond the needle point. A lens system in the guard allows observation of the surface from the inside. The surface (16) is radiused at its distal end, and the guard is hollow as far as this surface forming a chamber (17) tapering in the distal direction. The lens (20) is clear of the surface in the axial direction, and with the guard in the distal position the needle point (12) is level with that where the radiused surface (16) joins onto the cylindrical casing of the guard. The lens system (18) can be interchangeable, and lockable inside the guard in the axial direction.