|A speculum (Latin for "mirror") (plural specula or speculums) is
a medical tool for investigating body cavities, with a form
dependent on the body cavity for which it is designed. In old texts,
the speculum may also be referred to as a diopter or dioptra. Like
an endoscope, a speculum allows entry into a body cavity;
endoscopes, however, tend to have optics while a speculum is
intended for direct vision.
Vaginal and anal specula were used by the ancient Greeks and
Romans, and speculum artifacts have been found in Pompeii. A vaginal
speculum, developed by J. Marion Sims, consists of a hollow cylinder
with a rounded end that is divided into two hinged parts, somewhat
like the beak of a duck. The speculum is inserted into the vagina to
dilate it for examination of the vagina and cervix.
All specula were formerly made of metal, and sterilized after
use. However, many, especially those used in Emergency Departments
and Doctor's offices, are now made of plastic, and are sterile,
disposable, single-use items. Those used in surgical suites are
still commonly made of metal.
Types of specula
Specula come in a variety of shapes based on their purpose, in
any case the tube or blade(s) of the instrument allow the operator a
direct vision of the area of interest and the possibility to
introduce instruments for further interventions such as a biopsy.
The best-known specula are the bivalved vaginal specula; the two
blades are hinged and are "closed" when the speculum is inserted to
facilitate its entry and "opened" in its final position where they
can be arrested by a screw mechanism, so that the operator is freed
from keeping the blades apart.