Page 671 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat
P. 671
RepRoductive ` REPRODUCTIVE—ANATOmy RepRoductive ` REPRODUCTIVE—ANATOmy SectioN iii 627
Urethral injury Occurs almost exclusively in men. Suspect if blood seen at urethral meatus. Urethral
catheterization is relatively contraindicated.
Anterior urethral injury Posterior urethral injury
PART OF URETHRA Bulbar (spongy) urethra Membranous urethra
mECHANISm Perineal straddle injury Pelvic fracture
lOCATION OF URINE lEAK/blOOD Blood accumulates in scrotum Urine leaks into retropubic space
ACCUmUlATION If Buck fascia is torn, urine escapes into perineal
space
PRESENTATION Blood at urethral meatus and scrotal hematoma Blood at urethral meatus and high-riding
prostate
Retropubic
space
Deep penile Bloody
(Buck) fascia extravasation Torn intermediate
part of urethra
Perforation of spongy urethra Membranous
(rupture of Buck fascia)
urethra
Autonomic Erection—Parasympathetic nervous system Point, Squeeze, and Shoot.
innervation of male (pelvic splanchnic nerves, S2-S4): S2, 3, 4 keep the penis off the floor.
sexual response NO cGMP smooth muscle PDE-5 inhibitors (eg, sildenafil) cGMP
relaxation vasodilation proerectile. breakdown.
Norepinephrine [Ca ] smooth
2+
in
muscle contraction vasoconstriction
antierectile.
Emission—Sympathetic nervous system
(hypogastric nerve, T11-L2).
Expulsion—visceral and Somatic nerves
(pudendal nerve).
FAS1_2019_15-Repro.indd 627 11/7/19 5:52 PM
