The Relative Anatomy Of The Male Pelvic Organs

Sources: Surgical Anatomy

As the abdomen and pelvis form one general cavity, the organs contained

in both regions are thereby intimately related. The viscera of the

abdomen completely fill this region, and transmit to the pelvic organs

all the impressions made upon them by the diaphragm and abdominal walls.

The expansion of the lungs, the descent of the diaphragm, and the

contraction of the abdominal muscles, cause the abdominal viscera to

desc nd and compress the pelvic organs; and at the same time the muscles

occupying the pelvic outlet, becoming relaxed or contracted, allow the

perinaeum to be protruded or sustained voluntarily according to the

requirements. Thus it is that the force originated in the muscular

parietes of the thorax and abdomen is, while opposed by the counterforce

of the perinaeal muscles, brought so to bear upon the pelvic organs as

to become the principal means whereby the contents of these are

evacuated. The abdominal muscles are, during this act, the antagonists

of the diaphragm, while the muscles which guard the pelvic outlet become

at the time the antagonists of both. As the pelvic organs appear

therefore to be little more than passive recipients of their contents,

the voluntary processes of defecation and micturition may with more

correctness be said to be performed rather for them than by them. The

relations which they bear to the abdomen and its viscera, and their

dependence upon these relations for the due performance of the processes

in which they serve, are sufficiently explained by pathological facts.

The same system of muscles comprising those of the thorax, abdomen and

perinaeum, performs consentaneously the acts of respiration, vomiting,

defecation and micturition. When the spinal cord suffers injury above

the origin of the phrenic nerve, immediate death supervenes, owing to a

cessation of the respiratory act. Considering, however, the effect of

such an injury upon the pelvic organs alone, these may be regarded as

being absolutely excluded from the pale of voluntary influence in

consequence of the paralysis of the diaphragm, the abdominal and

perinaeal muscles. The expulsory power over the bladder and rectum being

due to the opposing actions of these muscles above and below, if the

cord be injured in the neck below the origin of the phrenic nerve, the

inferior muscles becoming paralysed, the antagonism of muscular forces

is thereby interrupted, and the pelvic organs are, under such

circumstances, equally withdrawn from the sphere of volition. The

antagonism of the abdominal muscles to the diaphragm being necessary, in

order that the pelvic viscera may be acted upon, if the cord be injured

in the lower dorsal region, so as to paralyse the abdominal walls and

the perinaeal muscles, the downward pressure of the diaphragm alone

could not evacuate the pelvic organs voluntarily, for the abdominal

muscles are now incapable of deflecting the line of force backwards and

downwards through the pelvic axis; and the perinaeal muscles being also

unable to act in agreement, the contents of the viscera pass

involuntarily. Again, as the muscular apparatus which occupies the

pelvic outlet acts antagonistic to the abdomen and thorax, when by an

injury to the cord in the sacral spine the perinaeal apparatus alone

becomes paralysed, its relaxation allows the thoracic and abdominal

force to evacuate the pelvic organs involuntarily. It would appear,

therefore, that the term "paralysis" of the bladder or rectum, when

following spinal injuries, &c. &c. means, or should mean, only a

paralytic state of the abdomino-pelvic muscular apparatus, entirely or

in part. For, in fact, neither the bladder nor rectum ever acts

voluntarily per se any more than the stomach does, and therefore the

name "detrusor" urinae, as applied to the muscular coat investing the

bladder, is as much a misnomer (if it be meant that the act of voiding

the organ at will be dependent upon it) as would be the name "detrusor"

applied to the muscular coat of the stomach, under the meaning that this

were the agent in the spasmodic effort of vomiting.



The urinary bladder, G, Plate 49, (in the adult body,) occupies the true

pelvic region when the organ is collapsed, or only partly distended. It

is situated behind the pubic symphysis and in front of the rectum,

C,--the latter lies between it and the sacrum, A. In early infancy, when

the pelvis is comparatively small, the bladder is situated in the

hypogastric region, with its summit pointing towards the umbilicus; as

the bladder varies in shape, according to whether it be empty or full,

its relations to neighbouring parts, especially to those in connexion

with its summit, vary also considerably. When empty, the back and upper

surface of the bladder collapse against its forepart, and in this state

the organ lies flattened against the pubic symphysis. Whether the

bladder be distended or not, the small intestines lie in contact with

its upper surface, and compress it in the manner of a soft elastic

cushion. When distended largely, its summit is raised above the pubic

symphysis, the small intestines having yielded place to it, and in this

state it can be felt by the hand laid upon the hypogastrium.



The shape of the bladder varies in different individuals. In some it is

rounded, in others pyriform, in others peaked towards its summit. Its

capacity varies also considerably at different ages and in different

sexes. When distended, its long axis will be found to coincide with a

line passing from a point midway between the navel and pubes to the

point of the coccyx, the obliquity of this direction being greatest when

the body is in the erect posture, for the intestines now gravitate upon

it. When the body is recumbent, the bladder recedes somewhat from the

pubes, and as the intestines do not now press upon it from above, it

allows of being distended to a much greater degree without causing

uneasiness, and a desire to void its contents.



The manner in which the bladder is connected to neighbouring parts is

such as to admit of its full distension. Its summit, back, and upper

sides are free and covered by the elastic peritonaeum, whilst its front,

lower sides, and base are adherent to adjacent parts, and divested of

the serous membrane. On tracing the peritonaeum from the front wall of

the abdomen to its point of reflexion over the summit of the bladder, we

find the membrane to be in this part so loosely adherent, that the

bladder when much distended, raises the peritonaeum above the level of

the upper margin of the pubic symphysis. In this state the organ may be

punctured immediately above the pubic symphysis without endangering the

serous sac. When the bladder is collapsed, the peritonaeum follows its

summit below the level of the pubes, and in this position of the organ

such an operation would be inadmissible, if indeed the necessity for it

can now be conceived.



By removing the os innominatum, A D, Plate 48, together with the

internal obturator, and levator ani muscles, which arise from its inner

side, we obtain a lateral view, Plate 49, of the pelvic viscera, and of

the vessels &c. connected with them. Those parts of the bladder, G, and

the rectum, C, which are invested by the peritonaeum, are also now fully

displayed. On tracing this membrane from before backwards, over the

summit of the bladder, G, we find it descending deeply upon the

posterior surface of the organ, before it becomes reflected so as to

ascend over the forepart of the rectum. This duplicature of the serous

membrane, H H, is named the recto-vesical pouch, and it is required to

ascertain with all the exactness possible the level to which it

descends, so as to avoid it in the operation of puncturing the bladder

through the rectum. The serous pouch descends lower in some bodies than

in others; but in all there exists a space, of greater or less

dimensions, between it and the prostate, V, whereat the base of the

bladder is in direct apposition with the rectum, W, the serous membrane

not intervening.



When the peritonaeum is traced from one iliac fossa to the other, we

find it sinking deeply into the hollow of the pelvis behind the bladder,

so as to form the sides of the recto-vesical pouch; but when traced over

the summit of the bladder, this organ is seen to have the membrane

reflected upon it, almost immediately below the pelvic brim. At the

situations where the peritonaeum becomes reflected in front, laterally,

and behind, upon the sides of the bladder, the membrane is thrown into

folds, which are named "false ligaments." The pelvic fascia, in being

reflected to the bladder from the front and sides of the pelvis, at a

lower level than that of the peritonaeum, forms the "true ligaments." In

addition to these ligaments, which serve to keep the base and front of

the bladder fixed in the pelvis, other structures, such as the ureters,

K, the vasa deferentia, I, the hypogastric cords, the urachus, and the

bloodvessels, embrace the organ in various directions, and act as

bridles, to limit its expansion more or less in all directions, but

least so towards its summit, which is always comparatively free.



The neck and outlet of the bladder, V, are situated at the anterior part

of its base, and point towards the subpubic space. The prostate gland,

V, surrounds its neck, and occupies a position behind and below the

pubic arch, D, and in front of the rectum, W. The gland, V, being of a

rounded form and dense structure, can be felt in this situation by the

finger, passed upwards through the bowel. The prostate is suspended from

the back of the pubic arch by the anterior true ligament of the bladder,

and at its forepart, where the membranous portion of the urethra

commences, this passes through the deep perinaeal fascia, X. The

anterior fibres of the levator ani muscle embrace the prostate on both

its sides. Behind the base of the prostate, the ureter, K, is seen to

enter the coats of the bladder obliquely, whilst the vas deferens, I,

joined by the vesicula seminalis, L, penetrates the substance of the

prostate, V, at its lower and back part, which lies in apposition with

the rectum.



The rectum, W C, at its middle and upper parts, occupies the hollow of

the sacrum, A Q, and is behind the bladder. The lower third of the

rectum, W, not being covered by the peritonaeum, is that part on which

the various surgical operations are performed. At its upper

three-fifths, the rectum describes a curve corresponding to that of the

sacrum; and if the bladder be full, its convex back part presses the

bowel against the bone, causing its curve to be greater than if the

bladder were empty and collapsed. This fact requires to be borne in

mind, for, in order to introduce a bougie, or to allow a large injection

to pass with freedom into the bowel, the bladder should be first

evacuated. The coccygeal bones, Q, continuing in the curve of the

sacrum, bear the rectum, W, forwards against the base of the bladder,

and give to this part a degree of obliquity upwards and backwards, in

respect to the perinaeum and anus. From the point where the prostate, V,

lies in contact with the rectum, W, this latter curves downwards, and

slightly backwards, to the anus, P. The prostate is situated at a

distance of about an inch and a half or two inches from the anus--the

distance varying according to whether the bladder and bowel be distended

or not. [Footnote]



[Footnote: The distance between any two given parts is found to vary in

different cases. "In subjects of an advanced age," Mr. Stanley remarks,

"a deep perinaeum, as it is termed, is frequently met with. This may be

occasioned either by an unusual quantity of fat in the perinaeum, or by

an enlarged prostate, or by the dilatation of that part of the rectum

which is contiguous to the prostate and bladder. Under either of these

circumstances, the prostate and bladder become situated higher in the

pelvis than naturally, and consequently at a greater distance from the

perinaeum."--On the Lateral Operation of Lithotomy.]



The arteries of the bladder are derived from the branches of the

internal iliac, S. The rectum receives its arteries from the inferior

mesenteric and pudic. The veins which course upwards from the rectum are

large and numerous, and devoid of valves. When these veins become

varicose, owing to a stagnation of their circulation, produced from

whatever cause, the bowel is liable to be affected with haemorrhoids or

to assume a haemorrhagic tendency.



The pudic artery, S s, is a branch of the internal iliac. It passes from

the pelvis by the great sciatic foramen, below the pyriformis muscle,

and in company with the sciatic artery. The pudic artery and vein wind

around the spine, E, of the ischium, where they are joined by the pudic

nerve, derived from, T, the sacral plexus. The artery, in company with

the nerve and vein, re-enters the pelvis by the small sciatic foramen,

and gets under cover of a dense fibrous membrane (obturator fascia),

between which and the obturator muscle, it courses obliquely downwards

and forwards to the forepart of the perinaeum. At the place where the

vessel re-enters the pelvis, it lies removed at an interval of an inch

and a half from the perinaeum, but becomes more superficial as it

approaches the subpubic space, N. The levator ani muscle separates the

pudic vessels and nerves from the sides of the rectum and bladder. The

principal branches given off from the pudic artery of either side, are

(1st), the inferior hemorrhoidal, to supply the lower end of the rectum;

(2nd), the transverse and superficial perinaeal; (3rd), the artery of

the bulb; (4th), that which enters the corpus cavernosum of the penis,

N; and (5th), the dorsal artery of the penis. [Footnote] The branches

given off from the pudic nerve correspond in number and place to those

of the artery. Having now considered the relations of the pelvic organs

in a lateral view, we are better prepared to understand these relations

when seen at their perinaeal aspect.



[Footnote: The pudic artery, or some one of its branches, occasionally

undergoes marked deviations from the ordinary course. In Mr. Quain's

work, ("Anatomy of the Arteries,") a case is represented in which the

artery of the bulb arose from the pudic as far back as the tuber ischii,

and crossed the line of incision made in the lateral operation of

lithotomy. In another figure is seen a vessel ("accessory pudic"),

which, passing between the base of the bladder and the levator ani

muscle, crosses in contact with the left lobe of the prostate.]





DESCRIPTION OF PLATES 48 & 49.



PLATE 48.



A. The anterior superior iliac spine.



B. The anterior inferior iliac spine.



C. The acetabulum; c, the ligamentum teres.



D. The tuber ischii.



E. The spine of the ischium.



F. The pubic horizontal ramus.



G. The summit of the bladder covered by the peritonaeum.



H. The femoral artery.



I. The femoral vein.



K. The anterior crural nerve.



L. The thyroid ligament.



M. The spermatic cord.



N. The corpus cavernosum penis; n, its artery.



O. The urethra; o, the bulbus urethrae.



P. The sphincter ani muscle.



Q. The coccyx.



R. The sacro-sciatic ligament.



S. The pudic artery and nerve.



T. The sacral nerves.



U. The pyriformis muscle, cut.



V. The gluteal artery.



W. The small gluteus muscle.














PLATE 49.



A. The part of the sacrum which joins the ilium.



B. The external iliac artery, cut across.



C. The upper part of the rectum.



D. The ascending pubic ramus.



E. The spine of the ischium, cut.



F. The horizontal pubic ramus, cut.



G. The summit of the bladder covered by the peritonaeum; G *, its side,

not covered by the membrane.



H H. The recto-vesical peritonaeal pouch,



I. The vas deferens.



K. The ureter.



L. The vesicula seminalis.



M, N, O, P, Q, R, S, T, U, refer to the same parts as in Plate 48.



V. The prostate.



W. The lower part of the rectum.



X. The deep perinaeal fascia.