Organ
Membranous urethra
The sphincter-associated segment below the prostate
High-yield
This relatively fixed segment lies near the prostatic apex, with bulbourethral glands posterolaterally and their ducts continuing toward the bulbar urethra.
Overview
The short membranous urethra connects the prostatic and bulbar regions. It passes through the external sphincter complex and perineal membrane, making its local muscular and fascial relationships central to continence and posterior urethral injury.
Reference facts
- Location
- Between prostatic apex and penile bulb, traversing the sphincter complex and perineal membrane.
- Parts
- A short urethral segment surrounded by striated sphincter tissue and associated smooth muscle and connective tissue.
- Blood supply
- Regional bulbourethral/internal pudendal branches with proximal prostatic vascular connections.
- Innervation
- Pudendal somatic pathways supply sphincter function, with pelvic autonomic and sensory contributions to the surrounding urethral region.
- Venous/Lymphatic drainage
- Venous channels communicate with prostatic and internal pudendal pathways; lymph reaches pelvic nodes.
- Relations
- External sphincter surrounds it; bulbourethral glands lie posterolaterally and drain farther distally into the spongy urethra.
- Function
- Conveys urine and semen through a region where striated muscle contributes importantly to continence.
Clinical correlation
Pelvic fracture can disrupt the bulbomembranous or adjacent posterior urethral region. Injury location and prostate displacement vary; a high-riding prostate is an unreliable finding. Scarring after trauma or instrumentation can later narrow the lumen.
Frequently asked questions
Where is the membranous urethra located?
Between prostatic apex and penile bulb, traversing the sphincter complex and perineal membrane.
What does the membranous urethra do?
Conveys urine and semen through a region where striated muscle contributes importantly to continence.
What are the parts of the membranous urethra?
A short urethral segment surrounded by striated sphincter tissue and associated smooth muscle and connective tissue.
What is the blood supply of the membranous urethra?
The membranous urethra is supplied by the regional bulbourethral/internal pudendal branches with proximal prostatic vascular connections.