See Also: annulus urethralis(medicine)
Herbal medicine (botanical medicine, herbology, phytomedicine)(health)
crista urethralis(medicine)
arteria urethralis(medicine)
colliculus urethralis(medicine)
habenula urethralis(medicine)
lacuna urethralis(medicine)
facies urethralis penis(medicine)
carina urethralis vaginae(medicine)
crista urethralis masculinae(medicine)

annulus urethralis (medicine)


annulus urethralis -->
sphincter vesicae


The complete collar of smooth muscle cells of the neck of the urinary bladder which extend distally to surround the preprostatic sportion of the male urethra. There is not a comparable structure in the neck of the femoral bladder; the internal urethral sphincter may exist to prevent reflux of semen into bladder.

Synonym: annulus urethralis, internal urethral sphincter, musculus sphincter vesicae, preprostate urethral sphincter, proximal urethral sphincter, sphincter muscle of urinary bladder.