Understanding Sphincter Size and Health : Insights into a Crucial Correlation

Sphincters are circular muscles that are present in our bodies and that open and close various passages in the body to regulate the flow of substances, including feces, urine, and bile, throughout the body.⁽¹⁾ Most of the sphincters are present in our gastrointestinal tract (GI tract), however, there are also urethral and anal sphincters. The size of these sphincters has so much to do with our health and well-being. Sphincter size is linked with specific health conditions.

Let us read below and take a closer look at this correlation between sphincter size and health conditions.

Fecal incontinence is one of the most devastating health conditions, which is associated with psychological, social, and economic consequences. This clinical condition affects between 2% and 15% of the adult population, and approximately 1 million to 7 million Americans are being adversely affected.^{(4, 5, 6, 7)}

A defect in the anal sphincter complex sustained during childbirth in many cases of women might result in fecal incontinence.⁽⁸⁾ However, the changes in size and function of the anal sphincter can also occur due to other reasons, and no matter what the reasons could be, anal sphincter size or malfunctioning of the anal sphincter can lead to fecal incontinence and chronic constipation in men and women.

The thickness of the internal anal sphincter (IAS) is known to increase with advancing age.^{(9, 10, 11)} There are two types of anal sphincters, including the internal anal sphincter and the external anal sphincter. The IAS plays a crucial role in maintaining continence.

Studies have shown the prevalence of anal incontinence and sphincter muscle atrophy due to growing age.⁽¹²⁾ A study has demonstrated a significant increase in both the diameter and thickness of the internal anal sphincter (IAS) in the elderly.⁽¹³⁾ This increase in the diameter and thickness or the size of IAS can increase the risk of incontinence.

The release of urine from our bladder is controlled by the internal and external sphincters of the urethra (urinary sphincters). Stress urinary incontinence (SUI) is a disorder caused by malfunctioning of the urinary sphincter and the condition refers to the involuntary leakage of urine from the external orifice with an increase in abdominal pressure, which could be due to actions like coughing, sneezing, or laughing.

Weakness or malfunctioning of these urinary sphincters can contribute to the urinary incontinence. When the urinary sphincter cannot effectively contract, the result is urinary incontinence.⁽³⁾ So, changes in the function, size, or tone of these sphincters can lead to health conditions like urinary incontinence.

The lower esophageal sphincter (LES) is a muscular ring located where the esophagus meets the stomach. It protects the esophagus from the reflux of gastric contents. An intrinsic and an extrinsic component makes the lower esophageal sphincter. Any malfunction in either of these components of LES can cause health issues like gastroesophageal reflux disease (GERD) and also a structurally defective lower esophageal sphincter, which might include the sphincter size.⁽²⁾

Sphincter size is somehow associated with certain health conditions. However, it should not be believed that it’s only the size of the sphincter alone that can be the sole criterion for the diagnosis of certain health conditions. So, when you find yourself in trouble because of any of the above-mentioned health conditions, such as GERD, urinary incontinence, or anything such, then make sure to visit your healthcare professional, and not just confirm that it might be a change in the size of sphincters that could be causing the diseased conditions. Your doctor would ask for your medical history, perform physical examinations, and various diagnostic tests for accurate assessment of your condition.

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