[Illustration: _Plate 3._
_Drawn by F.F. Giraud. 1823._ _Engraved by J. Stewart._
_London. Published 1824, by Longman, Hurst, Rees, Orme, Brown & Green._]
In this plate the section of the prostate gland is shewn; the parts being
viewed obliquely from before. The left hand of the operator holding the
staff is depressed to conduct the knife into the cavity of the bladder.
If attempt be made to depress the handle lower, the operator will feel
his hand checked by the ligament of the arch. The knife is seen piercing
the prostate in the direction which most nearly accords with Cheselden’s
section. This inclination of the knife will enable the operator to make
a very free incision, with great facility, without incurring any risk of
wounding the pudic artery, the rectum, or the veins surrounding the neck
of the bladder; unless a very large incision be required by the size of
the calculus, in which case some of the veins must necessarily be divided.
In contrasting this view with Plate I, it will be observed that the
prostate is carried somewhat upward from the rectum; this effect is
produced by the depression of the handle and the consequent elevation of
the extremity of the director. The danger of wounding the rectum is thus
still farther diminished.
One great advantage of conducting the operation on this principle arises
from the operator not being under the necessity of withdrawing the knife
from the groove of the staff, after he has once entered it, during the
subsequent steps of the operation. The extent of the incision in the
prostate and neck of the bladder may be regulated by the angle which
the knife makes in its introduction with the staff. Supposing that an
opening be required extending through the prostate from _d_ to _b_,
(which for the majority of calculi, even above the ordinary size, will be
quite sufficient, as the neck of the bladder will dilate considerably),
the point of the knife must be carried on as far as _a_ in the groove of
the staff. For it will be evident that if the same angle be maintained in
the act of carrying on the knife, the line _c b a_ will be the position
of the knife when the point has reached _a_. The edge of the knife,
although brought apparently so near to the rectum, will not injure it,
from its oblique inclination to the patient’s left side.