Where Is My Detrusor Muscle?
Hi friends! Have you ever heard of your detrusor muscle? Do you know where it is and what it does? If you have any troubles with urinary incontinence or go to the bathroom all day long, keep reading!
Detrusor is the fancy name for the muscle layer of the bladder. In our bodies we have two types of muscle: smooth muscle and skeletal muscle. When we think of muscle, we are typically talking about skeletal muscle. These muscles are the ones that move us and we have voluntary control over—when you want to move your arm to grab a cup of coffee, you are able to tell your brain to move those muscles.
Smooth muscle is a little bit different but it is found throughout our bodies, too. It is in our blood vessels, uterus, digestive tract, and it makes up the muscular layer of our bladder (the Detrusor). Unlike skeletal muscle, we don’t have voluntary control of when the muscle moves and works. Think about your digestive tract, your food moves along the stomach and intestines due to smooth muscle, but you don’t control it the same way we do our arms and legs.
Let’s talk about how the detrusor works. Your body filters blood to make urine (pee) in the kidneys. Once the kidneys have produced urine, it is sent to the bladder. This happens continuously throughout the day, so the bladder slowly fills. As it fills, the detrusor muscle is stretched. We have receptors in our bladder that measure how much it is stretched. Once it is stretched to a certain point, those receptors send a signal to the brain that it will need to empty soon. Normally this happens when the bladder is filled 40%--that means you still have 60% left to fill before your bladder is truly full. When the bladder has filled to about 60% full, the receptors then tell the brain it is time to find a bathroom.
Once you find a bathroom and are ready to pee, the pelvic floor muscles should relax while the detrusor contracts. The detrusor providers the pressure to get urine out of the bladder, and the pelvic floor muscles should relax to allow urine to exit the urethra.
What happens when the detrusor muscle isn’t working properly?
If the detrusor muscle is underactive, or not contracts as well or when it should, you might have difficulty with urinary retention. This can happen when you hold urine too long and stretch out the detrusor muscle (think teachers and nurses who don’t or can’t go to the bathroom during the day). This is sometimes called an atonic balder.
If the detrusor muscle is overactive, or contracting too frequently or too soon, this can lead to overactive bladder and urge urinary incontinence. If you go too often (I’m talking to those of you who always go to the bathroom “just in case”), you can stop the stretching of the detrusor which over time will make you need to go more.
Both overactivity and underactivity of the detrusor muscle have been linked to chronic pelvic pain (Goueli, 2017)
How do we treat issues with the detrusor? The way the brain and bladder work together is complicated, but a medical professional can help you determine the cause of urinary issues.
Pelvic floor physical therapy is great in most cases. A skilled therapist can help you address any issues with the pelvic floor muscles, bladder retraining, urge suppression techniques, and perform electrical stimulation to help the detrusor muscle (Firra, 2013). You can ask your healthcare provider for a referral to physical therapy, or find a pelvic therapist on your own at www.mypfm.com. We have links to 4 free searchable databases under Find a PT.
To learn more about your pelvic floor muscles, check out these great resources:
Learn more about the pelvic floor muscles with our book: My Pelvic Floor Muscles The Basics
Watch our YouTube playlist on Bladder Concerns and Your Pelvic Floor
Check out our favorite pelvic health items on Amazon
Sign up for our email newsletter!
For providers, check our online courses to help your clients with blad. Consider joining our Ambassador Program and most of our courses are included with your membership!
High Intensity PFMT Before & After Prostatectomy Improves Outcomes with Dr. Joanne Milios, PT, DPT
Urinary Incontinence and Urogynecology with Dr. Tessa Krantz, MD
The Hip and Urinary Incontinence: A look beyond the pelvic floor at what keeps us dry with Lauren Trosch, PT, DPT, OCS
An Innovative Way to Use Electrical Stimulation For Severe Pelvic Floor Dysfunction with Elizabeth Makous, MSPT, CLT, PRPC, CES
Nocturnal Enuresis with Dr. Charley Peterson, PT, DPT
Written by Emily Reul, PT, DPT
1. Goueli R et al. Characterization of bladder and pelvic floor dysfunction in women with chronic pelvic pain. J Womens Phys Therap. 2017;41(3):132-136.
2. Firra J, Thompson M, Smith SS. Paradoxical findings in the treatment of predominant stress and urge incontinence: a pilot study with exercise and electrical stimulation. J Womens Phys Therap. 2013;37(3):113-123.