BIOPSY INSTRUMENT

PROBLEM TO BE SOLVED: To provide a surgical instrument for excising a desired tissue part for biopsy from the nearby internal tissue of a surgery patient. SOLUTION: This instrument 10 includes a slender shaft 11, and a penetrating member 15 having a penetrating end for facilitating insertion of the shaft into the vicinity of the desired tissue part is mounted on the slender shaft 11. The instrument 10 includes a tissue accepting chamber 25 for accepting the desired tissue part for biopsy and a tissue cutter 26 movable from a first position to a second position in order to cut the desired tissue accepted in the tissue accepting chamber 25. The penetrating end has a blade 19 with first and second almost parallel planar surfaces. The blade 19 can decrease the force needed to pass the instrument 10 trough a tissue layer to place it near the part for biopsy. Also, the blade 19 works to facilitate tissue dilation during insertion of the instrument. Therefore, the combined effect of the decrease in the force needed to insert the instrument and expansion of the tissue can reduce injury to a patient and quicken the recovery of the patient.