and the bulb. Some portions of the rectum are separated from the surrounding parts by a considerable quantity of adipose and areolar tissue.

As the BLADDER, Fig. 187 (3, 4, 5), varies in size according as it is empty or distended, its relations to contiguous parts are necessarily modified. When empty, it is in relation an

7.

A SIDE VIEW OF THE VISCERA OF THE MALE PELVIS, IN SITU. THE RIGHT SIDE OF THE PELVIS HAS BEEN REMOVED BY A VERTICAL SECTION MADE THROUGH THE OS PUBIS NEAR THE SYMPHYSIS; AND ANOTHER THROUGH THE MIDDLE OF THE SACRUM.-1. The divided surface of the os pubis. 2. The divided surface of the sacrum. 3. The body of the bladder. 4. Its fundus; from the apex is seen passing upwards, the urachus. 5. The base of the bladder. 6. The ureter. The neck of the bladder. 8, 8. The pelvic fascia; the fibres immediately above 7 are given off from the pelvic fascia, and represent the anterior ligaments of the bladder. 9. The prostate gland. 10. The membranous portion of the urethra, between the two layers of the deep perineal fascia. 11. The deep perineal fascia formed of two layers. 12. One of Cowper's glands between the two layers of deep perineal fascia, and beneath the membranous portion of the urethra. 13. The bulb of the corpus spongiosum. 14. The body of the corpus spongiosum. 15. The right crus penis. 16. The upper part of the rectum. 17. The recto-vesical fold of peritoneum. 18. The lower portion of the rectum. 19. The right vesicula seminalis. 20. The vas deferens. 21. The rectum covered by the descending layer of the pelvic fascia. 22. A part of the levator ani muscle investing the lower part of the rectum. 23. The external sphincter ani. 24. The interval between the deep and superficial perineal fascia; they are seen to be continuous beneath the number. 25. Peritoneum covering the upper and back part of the bladder.

teriorly with the symphysis pubis, the pubic bones, and obturator muscles; and when distended, with the anterior walls of the abdomen. In the latter case, the peritoneum is raised

up so as to leave a non-peritoneal surface above the symphysis, when the bladder can be cut into for the purpose of removing calculi or evacuating its contents without injuring the peritoneum. It can also be perforated through the symphysis. Posteriorly, it is in contact, above, with the rectum and with the small intestines, and, when filled, with the sig moid flexure of the colon; below, with the vesiculæ seminales, the vasa deferentia, and the rectum. Sometimes, and especially when empty, the recto-vesical cul-de-sac extends down to the prostate gland and interposes between the vesical triangle and the rectum. It is through this triangular space that the bladder is sometimes perforated from the rectum. When this operation is performed it should be done close to the prostate gland to avoid the peritoneum, and in the median line, so as not to injure the vesicula seminales and the vasa deferentia. Laterally, the bladder is in relation on each side above, with the remains of the hypogastric artery and the vas deferens; and below, with the levator ani muscle and the pelvic fascia. Its neck, Fig. 187 (7), is in apposition with the prostate gland.

The bladder is retained in situ by ligaments, by fascia, and by the peritoneum. The ligaments of the bladder are designated the true and the false. The false consists simply of two folds of peritoneum, one on each side of the cul-de-sac between the bladder and the rectum; they are sometimes called the posterior ligaments of the bladder. The anterior true ligaments arise from the lower part of the pubic bones, and are inserted into the neck of the bladder. The lateral true ligaments are derived from the pelvic fascia, and will be described in connection with it.

The PROSTATE GLAND, Fig. 188 (2), is in relation, above, with the anterior ligaments of the bladder; on the sides with the levatores ani, and below, with the rectum. It is from two to two and a half inches above the anus. Its base corresponds to the neck of the bladder and its apex to the membranous portion of the urethra.

The relations of the membranous portion of the urethra and the bulb will be described in this place preparatory to the examination of the perineal fasciæ.

The MEMBRANOUS PORTION of the urethra, Fig. 187 (10), is situated below the arch of the pubes and extends from the

prostate gland to the bulb. It is in front of the rectum, from which it is separated by a triangular space, the base of which looks downwards and forwards towards the bulb and the

pe

ANTERO-POSTERIOR SECTION OF THE PELVIS OF A MALE, EXHIBITING THE VISCERA IN THEIR NATURAL SITUATION, AND THE CURVATURES OF THE URETHRA.--1. The bladder. 2. The prostate. 3, 3. The urethra, laid open through its whole extent. 4. The seminal vesicle, laid open. 5. The spongy body, seen both above and below the urethra. 6. The bulb of the spongy body. 7. The cavernous body of the penis. 8. The right side of the scrotum. 9. The rectum. 10. The peritoneal lining of the abdominal muscles. 11. The peritoneal investment of the bladder. 12. Tho point where the peritoneum is reflected from the bladder upon the rectum. 13. The section of the pubic symphysis. 14. A line marking the situation of the triangular ligament.

rineal centre; the apex is directed upwards and backwards to the point where the prostate gland rests against the rectum. It is about an inch below the symphysis, from which it is separated by an elastic and spongy structure, the muscles of Guthrie and Wilson, and the deep perineal fascia.

The BULB of the corpus spongiosum, Fig. 187 (13), corresponds to the upper part of the pubic arch, and is anterior to the triangular ligament. It is about three-fourths of an inch in front of the rectum. It is covered below by the in

tegument, the common superficial fascia, the superficial perineal fascia, and the ejaculatores urinæ muscles.

DISSECTION OF THE VESSELS AND NERVES IN THE PELVIC CAVITY.

The principal vessels and nerves in the pelvic cavity can be examined without removing any portion of the bones that form its parietes; to make a thorough dissection of them, however, the os innominatum on one side should be disarticulated and removed; or any portion of it may be cut away, including any part of the sacrum that may be found necessary in the progress of the dissection. The saw, or a mallet and chisel may be used for this purpose. To trace the vessels which supply the bladder and rectum, these organs should be moderately distended, the former with air, and the latter with cotton or tow. If the arteries be well injected but little difficulty will be encountered after the peritoneum has been removed, in exposing all the principal branches, as far as the organs which they supply or the openings through which they leave the pelvic cavity.

The Middle Sacral Artery seems to be a continuation of the aorta greatly diminished in size. It extends in the median line from the bifurcation of the aorta to the coccyx, passing over the body of the last lumbar vertebra and the sacrum. In its course it gives off small branches, some of which anastomose with the lateral sacral arteries, and others enter the

meso-rectum.

The INTERNAL ILIAC or HYPOGASTRIC ARTERY, Fig. 189 (6), Fig. 190 (6), furnishes most of the branches found in the pelvis. It arises from the bifurcation of the common iliac artery opposite the sacro-iliac symphysis, and descending into the pelvis terminates near the upper border of the great sacro-sciatic foramen. It varies in length from an inch to an inch and a half. Near its origin it is separated from the peritoneum by the ureter. The lumbo-sacral nerve lies behind it; the internal iliac vein is situated behind and a little to the outer side of it. In the foetus the internal iliac is continued to the umbilicus, where it becomes the umbilical artery. Commencing at the origin of the vesical artery a

ligamentous cord will be observed extending on the side of the bladder to the anterior parietes of the abdomen, and thence to the umbilicus; this is the remains of the hypogastric artery of the foetus. The folds of peritoneum formed by these fibrous cords, there being one on each side, were noticed in the examination of that membrane. The vasa

deferentia pass over these cords.

The branches of the internal iliac artery vary so much in their origin that no fixed rule, perhaps, need be observed in describing them. They will be noticed in the order in which it will be found most convenient to examine them in the dissection. The internal iliac very frequently divides into two principal trunks, from which the branches proceed. They are designated the anterior and posterior divisions, Fig. 189 (7, 8). When this division exists, the latter usually gives off

A DIAGRAM OF THE ILIAC ARTERIES AND THEIR BRANCHES.-1. The aorta. 2. The left common iliac artery. 3. The external iliac. 4. The epigastric artery. 5. The internal circumflex ilii. 6. The internal iliac artery. 7. Its anterior division. 8. Its posterior division. 9. The umbilical artery giving off (10) the superior vesical artery. After the origin of this branch the umbilical artery becomes converted into a fibrous cord-the umbilical ligament. 11. The internal pudic artery passing behind the spine of the ischium (12) and small sacro-sciatic ligament. 13. The middle hemorrhoidal artery. 14. The sciatic artery, also passing behind the small sacro-sciatic ligament to escape from the pelvis. 15. Its inferior vesical branch. 16. The ilio lumbar, the first branch of the posterior division (8) ascending to anastomose with the internal circumflex ilii artery (5), and form an arch along the crest of the ilium. 17. The obturator artery. 18. The lateral sacral. 19. The gluteal artery escaping from the pelvis through the upper part of the great sacro-sciatic foramen. 20. The sacra media. 21. The right common iliac artery cut short. 22. The femoral artery.