Urethral sphincters

Looks like

Rings of muscle around the start of the urethra: an inner involuntary one and an outer one under conscious control.

What it does

Hold urine in until you choose to pass it.

Keeping it well

Weakened by childbirth, menopause or prostate surgery; pelvic-floor exercises help stress incontinence and are the first treatment.

Related conditions

• Bedwetting (nocturnal enuresis)
• Benign prostatic hyperplasia
• Bladder cancer
• Bone metastases and spinal cord compression
• Botulism
• Fibromyalgia
• Frailty & falls in older age
• Heat exhaustion & heatstroke
• Interstitial cystitis (bladder pain syndrome)
• Intestinal worms & schistosomiasis
• Malnutrition & refeeding syndrome
• Muscular dystrophy
• Neurogenic bladder
• Obstructed labour and obstetric fistula
• Pelvic organ prolapse
• Polymyalgia rheumatica
• Rhabdomyolysis
• Sarcoma
• Sarcopenia
• Tetanus
• Urinary incontinence
• Urinary tract infection
• Vesicoureteral reflux