The internal urethral orifice is the opening of the
urinary bladder
The bladder () is a hollow organ in humans and other vertebrates that stores urine from the Kidney (vertebrates), kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. In humans, the ...
into the
urethra
The urethra (: urethras or urethrae) is the tube that connects the urinary bladder to the urinary meatus, through which Placentalia, placental mammals Urination, urinate and Ejaculation, ejaculate.
The external urethral sphincter is a striated ...
.
Anatomy
It is usually somewhat crescent-shaped.
Relations
It is formed by the
neck of the urinary bladder. It opens at the apex/inferior angle of the
trigone of the bladder, some 2-3 cm anteromedial to either
ureteral orifice.
The
mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...
immediately posterior to it presents a slight elevation in males - the
uvula vesicae - caused by the middle lobe of the
prostate
The prostate is an male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemica ...
.
See also
*
Internal sphincter muscle of urethra
References
External links
* - "The Male Pelvis: The Urethra"
Urinary system
Urethra
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