Biopsy needle having integral stylet locking device

Claim 1

An elongated hollow biopsy needle assembly with open distal or proximal ends, and with the distal end defining a cutting edge, said assembly including a cannula, an elongated stylet removably received within the bore of said cannula, a finger gripping means adjacent said proximal end, and coupling means for orienting said stylet within said cannula and for releasably securing said cannula to said finger gripping means; (a) said cannula being of uniform hollow, cylindrical configuration throughout the major portion of its length and having an external distal end surface tapered generally uniformly, uninterrupted, toward the tip of the distal end, and an internal end surface defining an inner biopsy tissue receiving and retaining bore immediately adjacent the distal end; (b) a generally cylindrical hub having a bore extending axially therethrough and securing the proximal end of said cannula to the inner diameter thereof, and with the bore of said hub forming an extension of the hollow cannula, a conical syringe receiving counterbore formed within the proximal end of said hub, and a radially disposed asymmetrical orientation surface formed along an end of said hub; (c) said elongated stylet being positioned within said cannula and corresponding generally in length and shape to the bore formed in said cannula, said stylet having a cap secured to the proximal end thereof with said cap having a radially disposed asymmetrical orientation surface formed therealong; (d) said finger gripping means including a generally centrally disposed coupling means with an inner surface having a radially extending asymmetrical surface mating with the radially disposed asymmetrical orientation surface of each of said cylindrical hub and said stylet cap for orienting said cannula relative to said stylet to present a closed asymmetrical end surface.