THE BLOOD VESSELS O F THE PROSTATE GLAND.

BY

GEORGE WALKER, M.D.

Associate in Hurgery, Johns Hopkins University.

From the Anatomical Laboratory, Johns Hopkins University.

WITH 2 COLORED PLATES.

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-ves- sels, 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. 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 sev- eral years late in appearing, i t should in reality have preceded those that were published in 1899.

I n 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 i t 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 fol- lowed by the injection of ultramarine-blue gelatine, which was kept up until no more of the material would pass in. The carmine gelatine

I n this search I was successful.

Walker, George: Ueber die Lymphgefasse der Prostata beim Hunde.

a Walker, George: Beitrag zur Kenntniss der Anatomie und Physiologie Arch. f u r Anatomie, 1899.

der Prostata, etc. Ibid., 1899. A M a R I C A N JOURNAL O F 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. I n 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 i t 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.

I n 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 car- mine 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. I n all, about 7 5 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 fol- lowed, i t 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 ordi- nary 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 a t 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 termi- nal 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; i t courses along the vesicorectal fascia and meets the prostate a t 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 di- rectly, 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 sub- stance of the gland and runs directly to the caput gallinaceum (Art. Col. Sem. Fig. 1). Rere it divides into a fine network and supplies the erec- tile tissue of the organ. Before this vessel reaches the eminence a small trunk is given off which extends to the ejaculatory duct (Art. duct. ej . Fig. 1). The branch supplying the caput gallinaceum is usually derived from the pudic; sometimes it comes from the inferior vesical.

The arterial supply in the connective tissue toward the urethra is much poorer than in the secreting portion. Here the vessels terminate in fine branches, relatively somewhat sparsely scattered. The arterial arrange- ment is shown on the red side of Figure 1.

CAPILLARIES.

The capillaries form a very complete and elaborate network around the alveoli of the lobule. Here, as is seen in Figure 3, they surround an alveolus in a more or less circular manner, and upon these vessels the cells rest almost directly, being separated only by the very delicate con- nective-tissue basement membrane. From this outside capillary, a fold- ing in is seen, which forms a definite loop (Gap. L. Pig. 3.) This at

George Walker 77

first sight might appear to end blindly, but a more careful study reveals the two branches, which sometimes appear winding around each other, and presenting enlarged club-shaped ends. The cells rest on these as they do on the circular portion. Under the low power, the epithelial cells appear to be in direct contact with the capillaries, and it is only by the aid of the oil immersion that a very delicate connective-tissue basement membrane is seen. This is shown artificially colored as B. M . Fig. 3. This membrane contains a few elastic fibers.

VEINS.

On the surface of the gland are veins corresponding to the arteries which lie in the capsule. As a rule they merge into two main trunks corresponding to the vesica! arteries ; occasionally several small branches pass off into the middle hemorrhoidal vein.

The superficial veins do not drain the blood from the whole gland, but only from the outer fourth, as is shown in Fig. 1. From the inner three- fourths of the gland the blood passes towards the centre, and into the large venous sinuses which are a continuation of the corpora spongiosa. (Co. Sp. Fig. 1). The large venous trunks which collect the blood from the gland do not lie on the same plane as the arteries, but are situated in the fibrous septa some little distance removed from them. These run, as do the arteries, on the outside of the lobule, and are interlobular, not intralobular. For the venous return from the caput gallinaceum there is no distinct vessel cor- responding with the artery, but there are anastomoses with the spongy plexus.

The venous plexus around the urethra is, as before stated, a continua- tion of the corpora spongiosa. The blood from this region passes away into the internal pudic vein. Occasionally two or t h e e small veins drain the tissues from this region, pass out of the prostate and run along the membranous urethra and off into the vesicorectal fascia.

There is an anastomosis of the veins in the prostate and bladder where these organs come together, and also on the outside through the superior vesical veins. There is, of course, an anastomosis of the urethral veins through the corpora spongiosa plexus.

These immediately surround the urethra.

SUMMARY.

The prostate gland is supplied with blood by branches of the internal iliac arteries, viz., the superior vesicals, inferior vesicals, inferior hemor- rhoidals, and internal pudics; the main blood supply comes from the inferior vesicals.

YS The Blood Vessels of the Prostate Gland

Branches of these envelop the surface of the gland and give off smaller

The capillaries are separated from the epithelial cells only by a very

There are superficial veins corresponding with the arteries. For ihc outer superficial fourth of the gland the return flow is towards

The inner three-fourths are drained by veins which empty

The lobule is formed primarily by the individual gland ducts as shown The main arteries surround this lobule which they pene-

The veins leave the lobule mainly at its peripheral

ones, which penetrate between the lobules in the fibrous-tissue septa.

thin basement membr ane.

the surface. into the venous plexus immediately around the urethra.

in Figure 2. trate at many points. and central (urethral) ends as shown in Fig. 1.

EXPLANATION O F PLATES I AND 11.

FIG. 1 is from a section of a prostate gland of a dog injected with carmine gelatine and ultramarine-blue gelatine. The arteries in the section were blue, the veins and capillaries red. The section was cut free hand, about 50:) in thickness, and cleared both in glycerine and in creosote. In the figure this artery is red and this vein blue. Art., Arteries; Art. Col. Xem.. Artery of the colliculus seminalis; Art. duct. ej. , Artery of the ejeculatory duct; Col. Xem., Colliculus seminalis; 77. PZ., Venous plexus around the urethra.

FIG. 2. Lobule of prostate from a gland which had been injected with ultramarine-gelatine blue into the artery, and with carmine gelatine into the prostatic duct. Pr. duct., Opening of the prostatic duct into the urethra; GZ. Tis., Gland tissues distended with carmine gelatine; Art., Surrounding artery. In this figure the artery is represented in red and the ducts in brown.

Capillaries in red, injected with carmine gelatine. Section stained with iron hematoxylin, with artificial yellow tinting of basement membrane. Oil immersion with one inch eye-piece amplification. Cap., Capillaries; B. M., Basement mem- brane; c f l . Ep., Glandular epithelium; Cap. L., Capillary loop.

FIG. 3. Very thin section from the prostate gland of a dog.