112 Commentary on plates 49 & 49.
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 48
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.
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 constitute 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 partition 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 sexual peculiarities are the results of the operation of this law, and all forms which are anomalous to either sex, 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 penis, the scrotum, 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 anus 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 penis; 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 vagina, or the anus 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 pubes. The adipose tissue, which in some subjects accumulates 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 testicles, E**, and penis 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 penis, which is a structure precisely median.