Page 134 - Clinical Anatomy

ECA2 7/18/06 6:43 PM Page 119

The male genital organs 119

The scrotum
The scrotum is the pouch in which lie the testes and their coverings. In cryp-
torchidism, not unnaturally, this pouch is not well developed.
The skin of the scrotum is thin, pigmented, rugose and marked by a lon-
gitudinal median raphe. It is richly endowed with sebaceous glands, and
consequently a common site for sebaceous cysts, which are often multiple.
The subcutaneous tissue contains no fat but does contain the involuntary
dartos muscle.

Clinical features

The scrotal subcutaneous tissue is continuous with the fasciae of the abdom-
inal wall and perineum and therefore extravasations of urine or blood deep
to this plane will gravitate into the scrotum. The scrotum is divided by a
septum into right and left compartments but this septum is incomplete supe-
riorly so extravasations of fluid into this sac are always bilateral.
The lax tissues of the scrotum and its dependent position cause it to fill
readily with oedema fluid in cardiac or renal failure. Such a condition must
be carefully differentiated from extravasation or from a scrotal swelling due
to a hernia or hydrocele.

Testis and epididymis (Figs 89, 90)
The left testis lies at a lower level than the right within the scrotum; rarely,
this arrangement is reversed. Each testis is contained by a white fibrous
capsule, the tunica albuginea, and each is invaginated anteriorly into a
double serous covering, the tunica vaginalis, just as the intestine is invagi-
nated anteriorly into the peritoneum.
Along the posterior border of the testis, rather to its lateral side, lies
the epididymis, which is divided into an expanded head, a body and a
pointed tail inferiorly. Medially, there is a distinct groove, the sinus
epididymis, between it and the testis. The epididymis is covered by the
tunica vaginalis except at its posterior margin which is free or, so to say,
‘extraperitoneal’.
The testis and epididymis each bear at their upper extremities a small
stalked body, termed respectively the appendix testis and appendix epididymis
(hydatid of Morgagni). The appendix testis is a remnant of the upper end of
the paramesonephric (Müllerian) duct; the appendix epididymis is a
remnant of the mesonephros.
These structures, being stalked, are liable to undergo torsion.

Blood supply

The testicular artery arises from the aorta at the level of the renal vessels. It
anastomoses with the artery to the vas, supplying the vas deferens and epi-
didymis, which arises from the inferior vesical branch of the internal iliac