PRACTICAL CONSIDERATIONS : PROSTATE GLAND. 1983 



Between these two capsules, or rather mainly embedded in the outer one, lies the 

 prostatic plexus of veins, most marked in front and on the sides of the prostate. The 

 larger arteries also lie between the true capsule and the sheath, numerous small 

 branches passing from them through the true capsule for the supply of the prostatic 

 substance. 



Freyer illustrates his view by imagining the edible portion of an orange composed 

 of two segments only, instead of several, with the septum between them placed 

 vertically, and says that the thin, strong, fibrous tissue which covers the segments of 

 the orange, and which is intimately connected with the pulp, would then represent 

 the true capsule of the prostate, the two segments or halves of the orange being rep- 

 resented by the two lobes of the prostate. Further, the rind of the orange would 

 represent the outer capsule or prostatic sheath, contributed by the pelvic fascia. In 

 the method of suprapubic prostatectomy now known by his name, it is the true cap- 

 sule as above described that is removed, the sheath being left behind, thus pre- 

 venting infiltration of urine into the cellular tissues of the pelvis. 



In most cases of hypertrophy of the prostate the overgrowth is adenomatous in 

 character, numerous encapsuled adenomatous tumors being found embedded within 

 the substance of the lobes and frequently protruding on their surfaces. They some- 

 times assume the form of polypoid outgrowths, which, however, are invariably en- 

 closed within the true capsule, which is pushed before them. 



As the lobes enlarge they bulge out and have a tendency, each enclosed within 

 its own capsule, to become more defined and isolated, thus recalling their separate 

 existence in early foetal life. They become more loosely attached along their com- 

 missures (particularly the upper one), which in the normal prostate unite them 

 above and below the urethra. And in the course of this change the urethra, with 

 its accompanying structures, is loosened from its close attachment to the inner sur- 

 faces of the lobes, thus facilitating its being detached and left behind uninjured in 

 the removal of the prostate. 



In the earlier stages of the adenomatous overgrowth the enlargement is proba- 

 bly entirely extravesical. Its expansion in this position is, however, limited by the 

 pubic arch above, the triangular ligament in front, and the sacrum below. As the 

 enlargement progresses, it advances in the direction of least resistance, — namely, into 

 the bladder. The sheath, which at the posterior aspect of the prostate is least de- 

 fined, becomes gradually thinner as the enlargement in this direction progresses, till 

 eventually the prostate has burst through it, and is then merely covered by the mucous 

 membrane of the bladder (Freyer). 



It has been asserted that what has here been called " capsule" is in the normal 

 prostate really only a thin outer non-glandular portion — cortex — containing both 

 muscular and fibrous tissue (Shattock), and that the envelope formed from the pros- 

 tate by the expansion of adenomata represents more than the " cortex" and contains 

 glandular tissue derived from the stretched and compressed outer portion of the 

 prostate (Wallace). 



However this question may ultimately be settled, the anatomical views set forth 

 above explain the separability of the mass of the prostate from {a) the prostatic 

 plexus of veins (avoiding hemorrhage), (3) the under surface of the recto-vesical 

 fascia (avoiding urinary infiltration), and (c) the prostatic urethra and ejaculatory 

 ducts (minimizing interference with micturition and with potency), which separa- 

 bility has been shown to be at least occasionally possible during operation. 



Perineal prostatectomy is done, with the patient in the lithotomy position, by 

 means of a semilunar incision in front of the anus carried down through the successive 

 structures of the urethral perineum until the sheath of the prostate is reached. After 

 division of the sheath on either side in a direction parallel with the medial fibres of 

 the levator ani, the prostate in its capsule — or portions of it — may be enucleated with 

 the finger. The gland may be made more accessible by downward pressure through 

 the space of Retzius (by means of a suprapubic incision) or through the bladder 

 itself (after a preliminary suprapubic cystotomy). It may be reached by a lateral 

 incision half encircling the anus. It should be remembered that it is separated from 

 the ischio-rectal fossa only by the levator ani muscle, with the visceral layer of the 

 pelvic fascia on its upper and the anal fascia on its lower surface. 



