PART I. THE ANATOMY OF THE PROSTATE. CHAPTER I. THE TOPOGRAPHICAL AND STRUCTURAL ANATOMY OF The Prostate as an Independent Organ.-Mode of Dissecting.-Limits of.-Form.— Size. Measurements. Weight. - External Relations.-Vessels and Nerves.— Anatomical Conformation; Lobes.-History of the "Third Lobe."-Prostatic Urethra, its Course and Character. - The Utricle. - Ejaculatory Ducts. MINUTE ANATOMY.-Its Fibrous Elements.-Its Glandular Elements.-Relative Proportions of.-Prostate Gland in Young Subjects. -Its Weight, Size, and Relations. In entering upon a study of the Pathology of the Prostate, there appears to exist a peculiar necessity for observing accurately its normal structure, conformation, and anatomical relations. The most common, as well as important, morbid states to which this organ is subject, either consist in, or are associated with, deviations from the natural size and form, as well as from the natural disposition of the structures entering into its composition. It is apparent that its anatomical relations also must, of necessity, be deranged, when the deviation from size in the direction of enlargement becomes considerable, as it not unfrequently does. Further, while the normal dimensions of the organ have been approximately determined, it is certain that the results which have been hitherto obtained are not based upon observations sufficiently numerous and extended definitively to settle the question, inasmuch as very different weights and measurements B are named in describing it by various authors. And lastly, our knowledge of its structure, to say nothing of its physiological uses, is, perhaps, less exact and defined, or, at all events, has been so until late years, than other topics in its history which are even less important to the student of disease. I propose, therefore, first to consider its normal anatomy in detail. In entering on this subject, it may be admitted that clearly defined marks are wanting in the structure of that part of the human organism, to which the term "prostate gland" is commonly applied, to indicate with exact precision its anatomical boundaries in every direction, or even to substantiate an undisputed title to its recognition as an independent organ, in that sense in which the word organ is very commonly understood. Forming a small portion of a large and important apparatus, which is continuous in structure throughout, it nevertheless exhibits peculiar characters in the arrangement and combination of its component tissues; a special appellation may be therefore regarded as appropriate and necessary for anatomical purposes. In like manner, a large and continuous division of the intestinal tube is recognized by anatomists as two separate portions, under the names of jejunum and ileum, although no physical boundary line indicates the limits of their proximal extremities; specialities of structure and function characterize each of these two portions, but those of the one glide insensibly into the other. Another important circumstance supports the custom of regarding the prostate as a separate organ, viz., the existence of such a structure, or of some analogous one, as an accessory to other sexual organs, throughout a very large portion of the animal series, not only in the Vertebrata, but in the Invertebrata also. And lastly, there is the consideration, of no little weight, which is supplied by the fact that the prostate is subject to morbid changes, which, as will be seen hereafter, are peculiar to it, and which do not occur in any adjacent or related structure. These remarks appear to be necessary at the outset, to explain DISSECTION TO DEFINE IT. 3 that, although the organ which is the subject of examination here does not possess characters so independent as those which belong to such glands as the liver, the kidney, or the pancreas, it nevertheless exhibits characters of a nature so peculiar and distinguishing, that we feel compelled to assign to it the possession of an individuality and integrity which may, perhaps, be somewhat overlooked, if we study it mainly or solely from that point of view which regards it only as a fractional portion of some greater whole. The name of "prostate," as applied to the part under consideration, is supposed to have been originated by anatomists, from the fact of its standing before, or anterior to, the bladder or vesiculæ seminales, in the supine position of the subject; its name of “gland," from the glandular structures which form a considerable part of its component tissues. The prostate gland of the adult is commonly described as resembling a full-grown chestnut in size and form; sometimes it is compared in the last-named character to the ace of hearts, the small extremity being directed downwards and forwards, and the base upwards and backwards, in the erect position of the body. Assuming for the present that there is a certain amount of truth in these analogies, we shall next inquire what is the nature of its relations with the bladder on the one hand, and with the urethra on the other, before proceeding to determine accurately its limits, size, and form. When the bladder, prostate, and vesiculæ seminales, as well as the urethra for two or three inches of its course anterior to the prostate, are removed from the body and are fairly isolated from the neighbouring parts by dissection, the prostate appears as a mass having the form of a short truncated cone flattened between its pubic and rectal aspects, the base of which surrounds the neck of the bladder and projects somewhat below it, while its blunted apex ends at the fascial partition which stretches across the angular interval between the pubic bones, and is known as the posterior layer of the deep perineal fascia. The bladder should be slightly distended with tow, and the parts above-named should be properly secured to facilitate the dissection, with the posterior or rectal aspect upward, from which it is understood that the rectum itself has been carefully removed, without removing more of the fascia than is necessary in the operation. First, will be seen, the vesiculæ seminales and vasa deferentia bound closely by a dense fascia to the posterior border of the prostate and base of the bladder adjacent, and requiring some careful dissection to isolate them fairly. Each vas deferens has a vesicula seminalis on its outer side, and approaches obliquely the median line as it courses forward to the base of the prostate, and just before entering, it joins the vesicular duct to form the ✓ common or ejaculatory duct. These two vessels should be carefully cleaned and traced, when they will be seen to perforate the mass in a deep central interlobular depression or notch, and to v enter it in the middle line side by side. A layer of fascia, a portion of the recto-vesical fascia, may be now dissected from the inferior surface and sides of the gland, for which it forms an enveloping sheath, and several venous sinuses will be encountered lying between it and the proper capsule of the prostate, especially along its lateral borders, where those vessels are found large and generally filled with coagula, particularly in elderly subjects; and sometimes in the latter containing also large phlebolithes. The proper capsule, which cannot be regarded as a mere offshoot from any adjacent fascia, but is a special envelope belonging to the prostate itself, although thin, is firm in texture, and defines clearly the form and limits of the prostate here. Proceeding with the dissection by turning upwards a little the peritoneum covering the bladder, if we next clean the external layer or longitudinal muscles of that viscus and trace them with care, some bands of the paler and less superficial fibres will be found inserted into the base of the prostate above the point where the ejaculatory ducts enter. These should next be divided, and the longitudinal layer be turned aside from the base of the bladder to the right and left of the middle line as well as the mutual interlacements DISSECTION OF THE PROSTATE. 5 of the different vesical coats permit, and the inner or circular layer comes into view. These, which are very pale in colour, should be defined at the base and neck of the bladder, where they are chiefly aggregated, being very thin and scattered above, since by tracing them forwards they will be found to be continuous with muscular fibres similarly arranged, and forming a considerable portion of the prostate itself; and in order to do this, the proper capsule must be partially removed, with the more superficial as well as the lateral portions of the prostate which do not strictly belong to the circular system of fibres, but which contain a large proportion of glandular structure intermingled with interlacing muscular and fibrous tissues, and which will be described when we consider the minute anatomy of the organ. Into this outer portion also, some fibrous prolongations of the capsule proceed, and minute vessels enter the prostatic substance with them. In order to trace the circular fibres of the bladder through the prostate, a prolonged and delicate dissection is necessary. With care and patience it is, however, quite demonstrable that complete continuity of structure exists to a considerable extent between the circular fibres of the bladder and the constituent fibres of the prostate, and that they are arranged around the tube of the urethra in the manner described. By carefully continuing the dissection, this annular series of fibres may be traced along that canal, diminishing in volume as we proceed in the anterior direction, as far as to the bulb of the urethra, where they stop, having extended over the whole of the membranous portion. In this latter situation they have dwindled down to a layer, from onehalf to one-third of a line in thickness, although quite distinct. If next we make a longitudinal incision in the axis of the prostatic urethra through these fibres with great care, we may turn them. aside and lay bare a longitudinal layer of delicate pale muscular fibres which lie immediately outside the mucous membrane which forms that canal. These are the muscular fibres which surround the urethra throughout great part of its course, and which have been described in somewhat different terms by Hancock, Hogg, |