aspects of the mons or the base of the penis and can also provide afferent
innervation to stimulate the cremasteric response, pulling the testicles
upward. The pudendal nerve (answer d)provides sensation to most of the
skin of the perineum as well as the motor supply to the perineal muscles.
The involuntary scrotal reflex can also be based on temperature (answer e):
warmth causes relaxation of the cremasteric (skeletal) and dartos (smooth)
muscle, whereas cold causes contraction of both the cremasteric and dar-
tos muscles.
420.The answer is a.(Moore and Dalley, pp 228–229.)It is very uncom-
mon. Varicocele usually occurs on the left side (~95%) and is rare on the
right(answer b).Left varicocele results from local venous congestion
caused by compression of the testicular vein as it passes beneath the usu-
ally full sigmoid colon. Testicular torsion (answer c),wherein a long
mesorchium (answer d)is a contributing factor, strangulates the testicular
artery, and produces testicular ischemia, not varicocele. Testicular torsion is
a medical emergency which normally presents in adolescents as sudden
testicular pain (Moore and Dalley, p 226).
421.The answer f.(Moore and Dalley, pp 319–320, 393.)A, c, and d.
Renal and ureteric calculi (laymen’s kidney stones) generally are formed in
the kidneys and then lodge at one of three locations: 1) at the junction of
the renal pelvis with the ureter; 2) as the ureters cross the external iliac ves-
sels at the pelvic brim; and 3) as the ureters pass through the wall of the
bladder(see Fig. 3.14 A, p 393 Moore & Dalley).Stones generally do not
lodge at the edge of the greater pelvis [answer b;all other answers (a, c, d,
and e)are incomplete]. The referred pain from ureteric calculi is usually
described as from “loin to groin” in that it often starts in back and side over
the kidney and then extends in a band down towards the labia majora or
scrotum (from T 11 to L2). Normally the pain is intermittent and comes
and goes in waves and may change in location, generally moving inferiorly
with time. Since the ureters undergo peristaltic movement, the calculi
often move with time. Depending on the chemical composition and shape
of the calculi they may either block urine flow or if spiky, stick into the
wall of the ureter. Kidney stone pain is often described as being worse than
labor pains. Treatments include pain relief and drinking lots of fluids, and
either lithotripsy (use of ultrasound waves to break up the stone) or phys-
ical removal (surgical) of the stone in severe cases.
548 Anatomy, Histology, and Cell Biology