internal urethral orifice(redirected from ostium urethrae internum)
1. the entrance or outlet of any body cavity.
aortic orifice the opening of the left ventricle into the aorta; called also aortic opening.
external urethral orifice urinary meatus.
internal urethral orifice the opening from the urinary bladder into the urethra at one corner of the trigone of the bladder.
left atrioventricular orifice (mitral orifice) the opening between the left atrium and ventricle of the heart.
pulmonary orifice (orifice of pulmonary trunk) the opening between the pulmonary trunk and the right ventricle of the heart; called also opening of pulmonary trunk.
right atrioventricular orifice (tricuspid orifice) the opening between the right atrium and ventricle of the heart.
in·ter·nal u·re·thral or·i·fice[TA]
the internal opening of the urethra, at the anterior and inferior angle of the trigone.
in·ter·nal u·re·thral or·i·fice(in-tĕr'năl yūr-ē'thrăl ōr'i-fis) [TA]
The internal opening or orifice of the urethra, at the anterior and inferior angle of the trigone.
internal urethral orifice
The opening from which the urethra makes its exit from the bladder.
See also: orifice