Urethra
The fibromuscular tubular conduit that conveys urine from the bladder neck to the outside of the body.
💬 In Plain English
The urethra is the tube that carries urine from the bladder to the outside world during urination. In females, the urethra is short, wide, and straight, making blockages very rare but making it easier for bacteria to climb in and cause bladder infections. In males, the urethra is much longer, narrower, and curves around the pelvic bones before traveling through the penis. In male cats, the penile urethra narrows down to the diameter of a tiny needle, making it extremely vulnerable to plugging with mucus and crystals during FLUTD.
🔬 Clinical & Technical Depth
For Vets & TechniciansFormal Clinical Definition
Fibromuscular tubular conduit originating at the internal urethral orifice of the bladder trigone and terminating at the external urethral meatus. In males, comprises prostatic, membranous (pelvic), and penile segments; in females, courses along the vaginal floor.
Why Veterinarians Use It
Veterinarians assess urethral patency by passing urinary catheters and evaluating contrast urethrograms during urinary straining.
Clinical Context Encountered
Discussed during emergency triage for blocked male cats, dogs with urethral stones, or urinary incontinence.
Clinical Reference Guide (Anatomical Structure)
Anatomical Location
Extending from the bladder neck through the pelvic canal to the external genitalia.
Normal Physiological Function
Conveys urine from the bladder to the exterior environment, while internal smooth and external skeletal sphincters maintain urinary continence.
🐕 vs 🐈 Species Differences
Male cats have an extremely narrow, tapered penile urethra that measures less than 1 mm in diameter at the tip, making them uniquely susceptible to physical plugs of matrix, red cells, and struvite crystals.
- •A blocked urethra prevents any urine elimination, leading to severe hyperkalemia, cardiac arrhythmias, and death within 24 to 48 hours—this is an immediate medical emergency.
❓ Questions to Ask Your Veterinarian
Take these actionable questions with you to your next clinic visit or appointment:
- 1Is the urethra completely obstructed by stones, mucus, or urethral spasm?
- 2Can a catheter be passed smoothly into the bladder, or is there resistance?
- 3If recurrent blockages occur, is a Perineal Urethrostomy (PU) surgery recommended to widen the opening permanently?
Academic & Clinical References
- Urethral Anatomy and Pathophysiology in Dogs and CatsOrganization: Merck Veterinary Manual • Accessed: 2026-01-10https://www.merckvetmanual.com