Part 36 (1/2)
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 r.e.c.t.u.m.
X. The deep perinaeal fascia.
[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]
Plate 49
COMMENTARY ON PLATES 50 & 51.
THE SURGICAL DISSECTION OF THE SUPERFICIAL STRUCTURES OF THE MALE PERINAEUM.
The median line of the body is marked as the situation where the opposite halves unite and const.i.tute a perfect symmetrical figure. Every structure--superficial as well as deep--which occupies the median line is either single, by the union of halves, or dual, by the cleavage and part.i.tion of halves. The two sides of the body being absolutely similar, the median line at which they unite is therefore common to both. Union along the median line is an occlusion taking place by the junction of sides; and every hiatus or opening, whether normal or abnormal, which happens at this line, signifies an omission in the process of central union. The s.e.xual peculiarities are the results of the operation of this law, and all forms which are anomalous to either s.e.x, may be interpreted as gradations in the same process of development; a few of these latter occasionally come under the notice of the surgeon.
The region which extends from the umbilicus to the point of the coccyx is marked upon the cutaneous surface by a central raphe dividing the hypogastrium, the p.e.n.i.s, the s.c.r.o.t.u.m, and the perinaeum respectively into equal and similar sides. The umbilicus is a cicatrix formed after the metamorphosis of a median foetal structure--the placental cord, &c.
In the normal form, the meatus urinarius and the a.n.u.s coincide with the line of the median raphe, and signify omissions at stated intervals along the line of central union. When between these intervals the process of union happens likewise to be arrested, malformations are the result; and of these the following are examples:--Extrusion of the bladder at the hypogastrium is caused by a congenital hiatus at the lower part of the linea alba, which is in the median line; Epispadias, which is an urethral opening on the dorsum of the p.e.n.i.s; and Hypospadias, which is a similar opening on its under surface, are of the same nature--namely, omissions in median union. Hermaphrodism may be interpreted simply as a structural defect, compared to the normal form of the male, and as a structural excess compared to that of the female.
Spina bifida is a congenital malformation or hiatus in union along the median line of the sacrum or loins. As the process of union along the median line may err by a defect or omission, so may it, on the other hand, err by an excess of fulfilment, as, for example, when the urethra, the v.a.g.i.n.a, or the a.n.u.s are found to be imperforate. As the median line of union thus seems to influence the form of the hypogastrium, the genitals, and the perinaeum, the dissection of these parts has been conducted accordingly.
By removing the skin and subjacent adipose membrane from the hypogastrium, we expose the superficial fascia. This membrane, E E E*, Fig. 1, Plate 50, is, in the middle line, adherent to B, the linea alba, and thereby contributes to form the central depression which extends from the navel to the p.u.b.es. The adipose tissue, which in some subjects acc.u.mulates on either side of the linea alba, renders this depression more marked in them. At the folds of the groin the fascia is found adherent to Poupart's ligament, and this also accounts for the depressions in both these localities. From the central linea alba to which the fascia adheres, outwards on either side to the folds of both groins, the membrane forms two distinct sacs, which droop down in front, so as to invest the t.e.s.t.i.c.l.es, E**, and p.e.n.i.s in a manner similar to that of the skin covering these parts. As the two sacs of the superficial fascia join each other at the line B, coinciding with the linea alba, they form by that union the suspensory ligament of the p.e.n.i.s, which is a structure precisely median.
The superficial fascia having invested the t.e.s.t.i.c.l.es each in a distinct sac, the adjacent sides of both these sacs, by joining together, form the median septum scroti, E, Fig. 2, Plate 50. In the perinaeum, Fig. 1, Plate 51, the fascia, A, may be traced from the back of the s.c.r.o.t.u.m to the a.n.u.s. In this region the membrane is found to adhere laterally to the rami of the ischium and p.u.b.es; whilst along the median perinaeal line the two sacs of which the membrane is composed unite, as in the s.c.r.o.t.u.m, and form an imperfect septum. In front of the a.n.u.s, beneath the sphincter ani, the fascia degenerates into cellular membrane, one layer of which is spread over the adipose tissue in the ischio-rectal s.p.a.ce, whilst its deeper and stronger layer unites with the deep perinaeal fascia, and by this connexion separates the urethral from the a.n.a.l s.p.a.ces. The superficial fascia of the hypogastrium, the s.c.r.o.t.u.m, and the perinaeum forming a continuous membrane, and being adherent to the several parts above noticed, may be regarded as a general double sac, which isolates the inguino-perinaeal region from the femoral and a.n.a.l regions, and hence it happens that when the urethra becomes ruptured, the urine which is extravasated in the perinaeum, is allowed to pa.s.s over the s.c.r.o.t.u.m and the abdomen, involving these parts in consequent inflammation, whilst the thighs and a.n.a.l s.p.a.ce are exempt. The tunicae v.a.g.i.n.ales, which form the immediate coverings of the t.e.s.t.i.c.l.es, cannot be entered by the urine, as they are distinct sacs originally protruded from the abdomen. It is in consequence of the imperfect state of the inguino-perinaeal septum of the fascia, that urine effused into one of the sacs is allowed to enter the other.
Like all the other structures which join on either side of the median line, the p.e.n.i.s appears as a symmetrical organ, D D, Fig. 2, Plate 50.
While viewed in section, its two corpora cavernosa are seen to unite anteriorly, and by this union to form a septum ”pectiniforme;”
posteriorly they remain distinct and lateral, F F, Fig. 2, Plate 51, being attached to the ischio-pubic rami as the crura p.e.n.i.s. The urethra, B, Fig. 2, Plate 50, is also composed of two sides, united along the median line, but forming between them a ca.n.a.l by the cleavage and part.i.tion of the urethral septum. All the other structures of the perinaeum will be seen to be either double and lateral, or single and median, according as they stand apart from, or approach, or occupy the central line.
The perinaeum, Figs. 1, 2, Plate 51, is that s.p.a.ce which is bounded above by the arch of the p.u.b.es, behind by C, the os coccygis, and the lower borders of, I I, the glutaei muscles and sacro-sciatic ligaments, and laterally by D D, the ischiatic tuberosities. The osseous boundaries can be felt through the integuments. Between the back of the s.c.r.o.t.u.m and the a.n.u.s the perinaeum swells on both sides of the raphe, A B, Fig. 3, Plate 50, and a.s.sumes a form corresponding with the bag of the superficial fascia which encloses the structures connected with the urethra. The a.n.u.s is centrally situated in the depression formed between D D, the ischiatic tuberosities, and the double folds of the nates.
The perinaeum, Fig. 3, Plate 50, is, for surgical purposes, described as divisible into two s.p.a.ces (anterior and posterior) by a transverse line drawn from one tuber ischii, D, to the other, D, and crossing in front of the a.n.u.s. The anterior s.p.a.ce, A D D, contains the urethra; the posterior s.p.a.ce, D D C, contains the r.e.c.t.u.m. The central raphe, A B C, traverses both these s.p.a.ces. The anterior or urethral s.p.a.ce is (while viewed in reference to its osseous boundaries) triangular in shape, the apex being formed by the pubic symphysis beneath A, whilst two lines drawn from A to D D, would coincide with the ischio-pubic rami which form its sides. The raphe in the anterior s.p.a.ce indicates the central position of the urethra, as may be ascertained by pa.s.sing a sound into the bladder, when the shaft of the instrument will be felt prominently between the points A B. Behind the point B, the sound or staff sinks deeper in the perinaeum as it follows the curve of the urethra towards the bladder, and becomes overlaid by the bulb, &c.