The punch is like a needle, only bigger. It's essentially a tube with one end sharpened. Doc twirls it on tissue to cut it in, removes tool, grabs tissue cylinder with forceps, pulls and cuts. Sounds worse than it is -- Local anesthesia, of course.

Here's a photo of a set of various sizes from 1.5 to 8mm (Hmm, that one's a bullet hole of 31 Caliber!), mine was 3mm:

http://www.claflinequip.com/ProductDetail/zoom.asp?img=CESS-5911-00.jpg

Also, I think the needles come in much longer lengths, like for kidney biopsy.

Age 67 1/2
Ventral Tongue SCC T2N0M0G1 10/05
Anterior Tongue SCC T2N0M0G2 6/08
Base of Tongue SCC T2N0M0G2 12/08
Three partial glossectomy (10/05,11/05,6/08), PEG, 37 XRT 66.6 Gy 1/06
Neck dissection, trach, PEG & forearm free flap (6/08)
Total glossectomy, trach, PEG & thigh free flap (12/08)
On August 21, 2010 at 9:20 am, Pete went off to play with the ratties in the sky.