Pierre Vernier, a French mathematician, engineer,
and scientist, in 1631 published a book in which he
described his invention, an instrument that he perfected
for accurately measuring length that has
become known as the Vernier caliper. Today, a
well-engineered digital Vernier caliper is capable of
providing highly accurate lesional and excisional
measurements to 0.01 mm without a shade of ambiguity
to this level of precision. An example of such an
instrument is demonstrated in Fig 1 (15-cm maximum)
(model SEL SV-03-150, Schlenker Enterprises
Ltd, Lombard, Ill). The thumb controls the easyturning
wheel while fine steel reference points move
in response to the thumb to provide one-handed
measurement. An easily readable measurement appears
on the digital monitor to the nearest 0.01 mm.
This instrument can be manually cleansed with
disinfectants but cannot be immersed and is not
autoclavible.