Bone marrow biopsy instrument

Claim 2

A bone cutting component of a bone marrow biopsy apparatus including an alignment needle, which comprises; a bone cutting assembly which comprises; i. a handle for rotation; attached to a first end of ii. a cylindrical shank having one end attacHed to said handle and the second end affixed to the proximal end of iii. a cannula having an open distal end defining a bone cutting point which comprises a top rake primary grind of from about 18* to about 20* to the longitudinal axis of said cannula, a cutting edge at an angle of from about 25* to about 30* to a line perpendicular with the longitudinal axis of said cannula, said cutting edge being peripherally relieved; said shank and said cannula being adapted to be received within the bore of said alignment needle of the bone marrow biopsy apparatus.

Claim 3

The apparatus of claim 1 wherein the handle for rotation is in the shape of a frustum, tapering toward the top.

Claim 4

The apparatus of claim 2 wherein the handle for rotation has splines around the periphery which run at an angle to the longitudinal axis of the cannula portion of from about 15* to about 20*.

Claim 5

The apparatus of claim 1 having a secondary grind top rake of 0* to the longitudinal axis of said cannula.

Claim 6

A bone marrow biopsy apparatus which comprises: A. an elongate hollow alignment needle which comprises: i. a handle defining a central bore open at both ends of said handle; ii. a cannula having an open distal end defining a soft tissue penetration and bone indenting point and an open proximal end joined to said handle so that said bore and the lumen of said cannula form an axial passage traversing the alignment needle; B. a bone cutting assembly which comprises: i. a handle for rotation; attached to a first end of ii. a cylindrical shank having a. a diameter such that said shank mates with and bears upon the enclosing surface of the aforementioned central bore when inserted therein; b. a second end; affixed to the proximal end of iii. a cannula having a. an open distal end defining a bone cutting point which comprises a top rake primary grind of from about 18* to about 20* to the longitudinal axis of the cannula, a cutting edge at an angle of from about 25* to about 30* to a line perpendicular with the cannula longitudinal axis, said cutting edge being peripherally relieved; b. a diameter less than the diameter of the lumen of the alignment needle cannula; c. a length exceeding the length of said alignment needle cannula; and d. an open proximal end attached to the second end of said shank; the shank and cannula portions of said bone cutting assembly being withdrawably mounted in the axial passage of said alignment needle.

Claim 7

A bone marrow biopsy apparatus which comprises: A. an elongate hollow alignment needle which comprises: i. a handle defining a central bore open at both ends of said handle; ii. a cannula having an open distal end defining a soft tissue penetration and bone indenting point and an open proximal end joined to said handle so that said bore and the lumen of said cannula form an axial passage traversing the alignment needle; B. a bone cutting assembly which comprises: i. a handle for rotation; attached to a first end of ii. a cylindrical shank having a. a diameter such that said shank mates with and bears upon the enclosing surface of the aforementioned central bore when inserted therein; b. a second end; affixed to the proximal end of iii. a cannula having a. an open distal end defining a bone cutting point which comprises a top rake primary grind of from about 18* to about 20* to the longitudinal axis of the cannula, a cutting edge at an angle of from about 25* to about 30* to a line perpendicular with the cannula longitudinal axis, said cutting edge being peripherally relieved; b. a diameter less than the diameter of the lumen of the alignment needle cannula; c. a length exceeding the length of said alignment needle cannula; and d. an open proximal end attached to the second end of said shank; the shank and cannula portions of said bone cutting assembly being withdrawably mounted in the axial passage of said alignment needle.

Claim 8

The apparatus of claim 1 wherein said cylindrical shank has a diameter substantially larger than the diameter of said lumen.

Claim 9

The apparatus of claim 1 wherein the penetration and bone indenting point comprises a primary grind at an angle of about 18* to about 22* from the cannula longitudinal axis; and lateral side bevels at an angle of about 34* to about 36* from the cannula axis, intersecting at the point.

Claim 10

The apparatus of claim 1 wherein the handle (A) (i) has finger grips.

Claim 11

The apparatus of claim 1 wherein the handle for rotation (B) (i) is in the shape of a frustum, tapering towards the top.

Claim 12

The apparatus of claim 9 wherein the handle for rotation (B) (i) has splines around the periphery which run at an angle to the longitudinal axis of the cannula portion (B) (iii) of from about 15* to about 20*.

Claim 13

The apparatus of claim 1 having a secondary grind top rake of 0* to the longitudinal axis of the cannula.