158 METHODS OF EXAMINATION
long. To use the instrument, the patient is placed in the dorsal or lithotomy position at the extreme edge of the examining couch. The posterior blade is passed first as with the Sims's instrument. The handle is then seized by the left hand and marked traction exerted in a downward direction. It should be noted that retraction of the perineum to an extreme degree may be produced without causing any undue pain or discomfort. The handle of the anterior or upper blade is then passed in a similar manner, care being taken to introduce the blade immediately below the urinary meatus. The two blades are separated as widely as possible, and if no general anaesthesia is used, precautions must be taken to avoid nipping the vaginal or vulval mucous membrane between the margins of the specula. In removing the instrument the anterior blade is withdrawn first.
Auvard's speculum (Fig. 84 (b)) has some advantages over other types, but can only be employed in the lithotomy position. It is chiefly used when exploration or small operative procedures have to be carried out by the vaginal route without the aid of skilled assistance. The instrument consists of a broad posterior vaginal blade, with a solid grooved handle weighted by a heavy rounded mass of lead situated about its centre. This increased weight of the handle takes the place of the downward traction usually exerted by the assistant, and so maintains the instrument in position. The groove in both blade and handle is to permit the escape of fluid used for douching purposes.
Pozzi's specula are essentially retractors for the vaginal walls and are of considerable value when it is necessary to expose fully the vaginal fornices and cervix. An assistant is necessary since four separate blades have to be introduced and held in position, the two lateral retractors being short broad blades. The anterior and posterior, on the other hand, are long and narrow.
The view obtained with any of these specula is very satisfactory, particularly if good illumination is secured by the aid of one of the many excellent electric mirrors now placed on the market. The only objection to their use is that with the exception of Auvard's instrument, an assistant is necessary if any manipulations are to be conducted whilst the speculum is in place. In the case of the ordinary Sims's duck-bill speculum, Hubert Roberts has devised a useful modification to obviate the services of an assistant in elevating the upper buttock by attaching a curved metal flange to the upper border of the handle. Specula of this nature undoubtedly give the best view of the cervix and are to be preferred to the tubular varieties.
Bi-valve and tri-valve specula are employed by some surgeons, particularly in the United States, although in this country they have not up to the present been received with so much favour as abroad. A very useful type is shown in Fig. 88. These
