69. Anatomy | Male and Female Pelvis and Perineum II

A 62-year-old male develops gross hematuria after traumatic placement of a Foley catheter. Imaging reveals retroperitoneal hemorrhage. Which portion of the urethra was most likely injured?
A. Pre-prostatic urethra
B. Prostatic urethra
C. Membranous urethra
D. Spongy urethra
E. External urethral orifice

C

• C. Membranous urethra – Rigid and short, passes through the perineal membrane; most prone to injury from Foley catheter placement.

• A. Pre-prostatic urethra – Short segment before prostate; rarely injured.

• B. Prostatic urethra – Traverses prostate, usually affected in BPH or prostate cancer, not catheter trauma.

• D. Spongy urethra – Runs through corpus spongiosum; may be injured in perineal trauma (“straddle injury”), not Foley catheter.

• E. External urethral orifice – Superficial, not associated with retroperitoneal hemorrhage.

A 3-month-old boy is brought for evaluation because his testes are not palpable in the scrotum. Surgery is scheduled to prevent infertility and malignancy risk. What is the most likely diagnosis?
A. Hydrocele
B. Cryptorchidism
C. Varicocele
D. Testicular torsion
E. Prostate hypertrophy

B

• B. Cryptorchidism – Undescended testes detected at birth; increases infertility and malignancy risk; requires surgical correction.

• A. Hydrocele – Fluid-filled swelling from persistent processus vaginalis; transilluminates.

• C. Varicocele – Dilated pampiniform plexus; feels like “bag of worms.”

• D. Testicular torsion – Acute scrotal pain, absent cremasteric reflex.

• E. Prostate hypertrophy – Not relevant in infants.

A 35-year-old male presents with erectile dysfunction. Neurologic testing reveals impaired parasympathetic outflow from the pelvic splanchnic nerves. Which physiologic event is most directly affected?
A. Contraction of bulbospongiosus muscle
B. Contraction of ischiocavernosus muscle
C. Release of nitric oxide causing dilation of helicine arteries
D. Ejaculation mediated by sympathetic neurons
E. Relaxation of the external urethral sphincter

C

• C. Release of nitric oxide causing dilation of helicine arteries – Parasympathetic (pelvic splanchnic) fibers trigger erection by releasing nitric oxide → smooth muscle relaxation → increased cavernosal inflow.

• A & B – Somatic (pudendal) control; compress veins to maintain erection.

• D – Sympathetic control; causes emission and ejaculation (“Shoot”).

• E – Voluntary control via somatic innervation, not parasympathetic.

A 14-year-old boy reports swelling in his right scrotum. Physical examination reveals a fluid-filled, transilluminating mass surrounding the testis. The condition results from persistence of which embryologic structure?
A. Processus vaginalis
B. Gubernaculum
C. Paramesonephric duct
D. Mesonephric duct
E. Tunica albuginea

A

• A. Processus vaginalis – Failure to obliterate this peritoneal outpouching allows fluid accumulation → hydrocele.

• B. Gubernaculum – Anchors testes (→ scrotal ligament) or becomes round ligament in females.

• C. Paramesonephric duct – Female structure; forms uterus, tubes.

• D. Mesonephric duct – Male reproductive ducts (epididymis, vas deferens).

• E. Tunica albuginea – Dense fibrous layer covering testis; unrelated.