PROSTATE GLAND. (Corpus glandu losum ; lIpoankru, Gr. ; die Vorsteherdruse, Germ.; La Prostate, Fr.).—The prostate is a glandular body surrounding the neck of the bladder and beginning of the urethra of the male, deriving its name from its p.osition in front of the vesicul seminales. It N situated in the anterior part of the pelvis, behind and below the level ofthe symphysis pubis, posterior to the triangular ligament of the urethra, with which it is connected by a continuation of the latter with its capsule. It has the mem branous part of the urethra in front of it, and somewhat below its level, and it rests upon the anterior surface of the middle of the rec tum. The prostate is peHbrated by the ure thra, two thirds of the gland are below this canal ; it inclines obliquely downwards and forwards from behind, its apex being situated rather below the base.
In shape the prostate resembles a Spanish chesnut, or the ace of hearts on playing cards, and presents a base behind and an apex in front ; it is compressed from before back wards ; its sides are convex, and its base is notched. From base to apex the prostate measures from an inch to an inch and a quar ter ; from side to side, from an inch'and a half to two inches; and from half an inch to an inch in depth from before backwards : a healthy prostate weighs five or six drachms. This measurement nearly accords m ith that given by Dupuytren, who devoted much at tention to this subject, as having a most im portant bearing upon the bilateral operation of lithotomy.
A correct knowledge of the relations of this body to the adjacent viscera is of the highest practical importance. lf, after the introduc tion of a catheter through the urethra into the bladder, the finger be passed into the rectum, and carried forward, the bulb of the urethra is first indistinctly felt, behind which is the membranous portion; whilst beyond this, and still within reach of the finger, the prostate is perceived. In the empty state of the blad der the outline of this body is usually distinct enough ; but when the bladder is over dis tended with urine it becomes in a great mea sure confounded with the posterior surface of this viscus, and cannot be easily distinguished. To obtain a good view of the connections of the prostate, a side view of the pelvis should be prepared in the ordinary manner, by the removal of the left os innominatum, with the soft structures in immediate connection with it, leaving a small portion of the sym physis and ramus of the os pubis, together with the spine and a part of the ramus of the ischium. In this manner the levator ani is first brought into view, at the upper edge of which is seen the point of division of the pelvic fascia into the vesical and obturator. The levator ani has no immediate connection with the prostate, for, although it gives it a general lateral support, it is separated from it by the vesical fascia. Internal to the leva tor ani lie the vesical fascia and the levator prostat muscle. The vesical fascia is con tinuous with the pelvic, it passes inwards over the prostate, rectum, and bladder, inclosing these structures in separate sheaths. Thus
the prostate gets a complete investment from it ; this covering is above continuous with the anterior true ligaments of the bladder, in front it is connected with the posterior layer of the deep perinmal fascia, and beneath, the fascia passes between the gland and the rectum; thus the gland is completely invested by a fibrous capsule. This envelope incloses within it the prostatic plexus of veins, and the blood-vessels and nerves of the prostate; the veins are continuous in front with the dorsal vein of the penis, and behind with branches terminating in the internal iliac vein. Many branches of the prostatic venous plexus are necessarily divided in the lateral operation for the stone ; and in old persons, from their in creased size, they occasionally pour out so large a quantity of blood as to endanger the life of the patient, They often contain cal culous concretions, to which the term phle bolithes has been given. The following is the mode of connection between the prostate and the coats of the bladder ; the mucous coat is of course continuous from the bladder to the urethra ; the submucous cellular coat is firmly adherent to the capsule of the gland, whilst the inferior fibres of the detrusor urinm are arranged thus, the longitudinal fibres split into two la3.ers, one, the thickest, adheres to the submucous cellular coat of the bladder just behind the prostate; and the other, thin and indistinct, is implanted into the base of the gland itself. Harrison has described a long, delicate, and distinct band of muscular fibres as entering the notch in the base of the gland, beneath the uvula vesicm and middle lobe, into which it is sometimes inserted ; but it can frequently be traced nearly an inch further to be inserted into the veru montanum.* I can not satisfy myself of the existence of any muscular fibres at the under surface of the prostate. On either side of the gland we perceive a muscle, the levator prostato. It is frequently confounded with the anterior edge of the levator ani, from which however it is occasionally separated by a layer of cellu lar tissue. It arises from the posterior part of the symphysis pubis by a tendinous slip, and its origin extends for a short distance backwards from the anterior true ligament of the bladder of the corresponding side ; as it descends, its fibres spread out over the side of the prostate, and are inserted into the under part of its capsule ; its use is to sup port the gland, and by compressing it laterally to assist in the evacuation of its ducts. The prostate rests on the anterior surface of the rectun), a thin layer of fascia passing under neath the gland and the vesiculae seminales. Behind the prostate are the vesiculm, which diverge from each other as they recede, and are in front received into the interval between the lateral lobes, their anterior extremities are placed beneath the third lobe ; the vasa defe rentia run on their inner side,and the common ejaculatory ducts pass upwards in a curved direction, between the lateral and middle lobes, to terminate by the side of the sinus pocu laris.