Internal sphincter muscle of urethra

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Internal sphincter muscle of urethra
Coronal section of anterior part of pelvis, through the pubic arch. Seen from in front. (Region visible, but muscle not labeled.)
Urinary bladder (Region visible, but muscle not labeled.)
Latin	musculus sphincter urethrae internus
Origin	Pubis ramus
Insertion	Median raphe
Artery:
Nerve:	Pudendal nerve
Action:
Dorlands /Elsevier	m_22/13540450

The internal sphincter muscle of urethra is a muscle which constricts the internal urethral orifice. It is the junction of the urethra with the urinary bladder. The muscle is made of smooth muscle, so therefore it is under involuntary control. This is the primary muscle for constricting the release of urine.

v • d • e Anatomy: urinary system Abdomen Kidneys • Ureters • Orifice of ureter Pelvis Urinary bladder (Uvula, Trigone, Detrusor, Apex, Neck) Urethral sphincters (External sphincter muscle of male urethra, External sphincter muscle of female urethra, Internal sphincter muscle of urethra) Urethra Development Development of the urinary and reproductive organs