Detrusor muscle

The fibers of the detrusor muscle arise from the posterior surface of the body of the pubis in both sexes (musculi pubovesicales), and in the male from the adjacent part of the prostate. These fibers pass, in a more or less longitudinal manner, up the inferior surface of the bladder, over its apex, and then descend along its fundus to become attached to the prostate in the male, and to the front of the vagina in the female. At the sides of the bladder the fibers are arranged obliquely and intersect one another.

The three layers of muscles are arranged longitudinal-circular-longitudinal from innermost to outermost.

During urination, the detrusor muscle is contracted via parasympathetic branches from the pelvic splanchnic nerves to empty the bladder.[1] At other times, the muscle is kept relaxed via sympathetic branches from the inferior hypogastric plexus to allow the bladder to fill.[1]

In older adults over 60 years in age, the detrusor muscle may cause issues in voiding the bladder, resulting in uncomfortable urinary retention.[2]

The mucosa of the urinary bladder may herniate through the detrusor muscle.[3] This is most often an acquired condition due to high pressure in the urinary bladder, damage, or existing connective tissue disorders.[3]

• External sphincter muscle of female urethra
• External sphincter muscle of male urethra
• Internal urethral sphincter

• Histology at KUMC urinary/renal18-{{{2}}}
• Detrusor myectomy for detrusor overactivity: 1-year follow-up