The Blood Vessels of the Prostate Gland

THE BLOOD VESSELS OF THE PROSTATE GLAND. BY GEORGE WALKER, M.D. Associate in Hurgery, Johns Hopkins University. From the Anatomical Laboratory, Johns Hopkins University. WITH 2 COLOREDPLATES. AS the structures of the body are being more and more carefully in- vestigated it is found that organs are composed of like structural units, which when repeated a number of times form the whole organ. In gen- eral these units are formed by the glandular structures, the blood-vessels, or by both, as is the case in the liver. Some eight years ago, at the suggestion of Dr. Mall, I undertook the study of the prostate gland, with the hope of finding structural units in it. In this search I was successful. Since then my work has been continued in the laboratories of Professor Born' of Breslau and Pro- fessor Spalteholz ' of Leipzig, and although this communication is several years late in appearing, it should in reality have preceded those that were published in 1899. In the present study for the most part the prostate glands of dogs were used. Several cadavers were injected and the gross blood supply was studied in part from these. After the animals had been killed by chloro- form, the aorta was exposed just above the bifurcation and injected with various substances. A preliminary washing out of the blood-vessels with salt solution was practised in a few of the first injections, but this was soon discarded as it did not seem to enhance the value of the method. Carmine gelatine, followed by ultramarine-blue gelatine, as an injecting mass, gave the most satisfactory results. About 250 cc. of the carmine gelatine were injected first, the injection being stopped as soon as all of the tissues had acquired a maximum carmine hue. This was followed by the injection of ultramarine-blue gelatine, which was kept up until no more of the material would pass in. The carmine gelatine Walker, George: Ueber die Lymphgefasse der Prostata beim Hunde. Arch. fur Anatomie, 1899. a Walker, George: Beitrag zur Kenntniss der Anatomie und Physiologie der Prostata, etc. Ibid., 1899. AMaRICAN JOURNAL OF ANATOMY.-VOT,.v. .7 4 The Blood Vessels of the Prostate Gland filled the arteries, capillaries, and veins ; the blue passed into the arteries and arterioles, displacing the gelatine and filling them, but was stopped at the capillaries because the ultramarine-blue granules were too large to enter them. In a specimen thus prepared the. arteries appear blue, and the capillaries and veins red. This is shown in Figure 1, with colors reversed, in order to present the conventional appearance. As it was inipossible to get a perfectly complete injection in one specimen, several of the best were selected and the gaps filled in, with the results as shown in Fi,gure 1. One section, however, is remarkably beautiful and presents a picture very closely resembling that seen in this figure. In order to map out the complete network of arteries surrounding a separate lobule, I injected them with Prussian blue, then opened the urethra, and injected carmine gelatine into a prostatic duct through a very fine blunt hypodermic needle. A specimen made in this way is shown in Figure 2 where the ducts ard represented in brown. The capillaries were studied in a specimen which had been completely iiijccted with carmine gelatine. A very thin section of this was stained with iron hzma- toxylin, and is shown in Figure 3. The basement membrane is arti- ficially tinted with yellow so as to niake it visible. The technique of the injecting is rendered difficult by the fact that the situation of the gland in the pelvis is somewhat remote. In all, about 75 dogs were used before a complete circulation cycle could be seen. Cinnabar, lampblack, and various other substances were tried, but they did not prove as good as the combination of carmine gelatine followed by ul tramarine-blue gelatine. When the ordinary directions for preparing carmine gelatine were followed, it always proved difficult to get a perfectly transparent substance. The trouble is connected with the neutralization of the ammonia by the acetic acid. The gelatine should be rendered practically neutral, but if the reaction is carried the least bit too far, the solution becomes cloudy. Sometimes two drops of the acetic acid are sufficient to make turbid a whole litre of the prepared carmine. After a good many trials, the following method was adopted: Take 10 cc. of the ordinary laboratory ammonia and dilute with 40 cc. of distilled water, then determine by titration the exact amount of the laboratory acetic acid which will neutralize it. After this determination has been made, 10 ,grms. of pure carmine are rubbed up with 50 cc. of distilled water; then 25 cc. of the ordinary ammonia are measured, and a few drops at a time are poured into the carmine mixture which is kept constantly rubbed up. This process is very closely watched, and tJie ammonia is gradually added until the carmine is completely dissolved, and the mixture becomes George Walker 75 translucent and assumes a dark red color. The amount of ammonia used is determined by referring to the vessel in which the 25 CC. have been measured. The gelatine in whatever proportion it is required-according as a thin or thick solution is desired-is dissolved in the distilled water, and the carmine solution is added to it. We then calculate how much acetic acid will be required for the amount of ammonia which has been used; this is measured and added, drop by drop, to the mixture which is constantly stirred. A sufficient quantity of water is then added to bring the amount up to a litre. I found that in this way I could always obtain a beautifully clear gelatine and was never annoyed by the failures and uncertainties belonging to the other method. ARTERIES. The prostate gland derives its arterial supply from the internal iliac arteries by means of four branches; the superior vesical, the inferior vesical, a small branch from the inferior hemorrhoidal, and a small terminal branch from the internal pudic artery. These vessels will be found illustrated in my paper published in 1899. The superior vesical, a branch from the internal iliac, which is given off high up, divides before reaching the bladder, into two fair-sized branches; the lower and smaller branch extends downward and supplies the vesical third of the prostate ; this branch is sometimes called the middle vesical artery. The inferior vesical, which is a large branch, is practically the main blood vessel of the prostate gland, and should be called the prostatic artery for, in the majority of instances, it does not send any branches to the bladder. The major part of the gland is supplied by this vessel; it courses along the vesicorectal fascia and meets the prostate at its lower border, where it usually divides into seven branches, four of these enveloping the anterior, and three the posterior surface. The posterior are about one-half the size of the anterior branches. These vessels are situated in the capsule of the gland and envelop it as the fingers of one’s hand would do in clasping a round object. From these trunks a number of smaller ones are given off, so that a very close arterial network is formed over the surface of the gland. The branch from the inferior hemorrhoidal is not constant; in fact, it appears to be more often absent than present. When it is seen, it occurs as one or two small branches which meet the prostate in its urethral half, and extend over the surface as fine vessels which anastomose with the vesical artery. The internal pudic branch is fairly constant. It extends along the membranous urethra and plunges directly into the prostatic substance usually without giving off any branches to the surface. 5'6 The Blood Vessels of the Prostate Gland A slight anastomosis is occasionally seen. The vessels supplying the two sides of the gland are distinct. The only anastomosis across the median line is by way of the venous channels around the urethra. From the large superficial branches above described, smaller ones are given off at right angles, and pierce the gland in places corresponding to the divisions of the lobules (Art. Fig. 1). Here they penetrate the fibrous-tissue septa, and extend to the urethra, becoming smaller and smaller, however, as they approach it, so that in this region they are seen as very delicate terminal vessels. As they pass down, they give off branches which penetrate into the lobule and finally divide into myriads of capillaries which pass around the alveoli, and come in very close relationship with the secreting cells. From these cells they are separated simply by a delicate basement membrane composed of fine fibrils. From the superficial vessels branches are given off which enter the lobule directly, that is, they do not pass first into the fibrous-tissue septa (Sup. Br. Fig. 1). On the anterior surface there are usually two branches which do not give off as many smaller ones as the rest, and consequently remain larger and extend over to the middle line, where they dip into the median fissure and supply the median side of the lobules (Med. Br. Fig. 1). The arrangement on the posterior surface corresponds to that seen on the anterior surface, in so far as the supply of the lobules is concerned. On the posterior surface toward the bladder one vessel penetrates the substance of the gland and runs directly to the caput gallinaceum (Art.

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