Can a patient with a history of depression, anxiety, and fatigue, who has undergone surgery, voluntarily contract their internal anal sphincter muscle in the same way as their external anal sphincter muscle during bowel movements?

Voluntary Control of Anal Sphincter Muscles

You cannot voluntarily contract your internal anal sphincter muscle—only the external anal sphincter is under voluntary control. The internal sphincter is composed of smooth muscle controlled by the autonomic nervous system, while the external sphincter is striated muscle that responds to conscious commands 1.

Anatomical Distinction Between Sphincter Muscles

The two sphincter muscles have fundamentally different properties:

• External anal sphincter: Composed of striated muscle under voluntary control that can be consciously contracted and strengthened through pelvic floor muscle training 1
• Internal anal sphincter: Composed of smooth muscle under involuntary autonomic control that cannot be strengthened through voluntary exercise training 1

This anatomical difference means that when you consciously "squeeze" or contract your anal sphincter, you are only activating the external sphincter 1.

What You Feel During Bowel Movements

During normal bowel movements, the internal sphincter relaxes reflexively (the rectoanal inhibitory reflex) when stool enters the rectum 2. This relaxation is completely involuntary and automatic. The external sphincter can then be voluntarily contracted to delay defecation if the timing is inconvenient, or voluntarily relaxed to permit defecation 2.

The sensation of "holding it in" comes entirely from voluntary contraction of your external sphincter opposing the involuntary relaxation of your internal sphincter 2. You cannot consciously control the internal sphincter's relaxation—you can only use the external sphincter to compensate for it.

Clinical Implications for Post-Surgical Patients

For patients with depression, anxiety, and fatigue following surgery, several considerations apply:

• Pelvic floor muscle training can strengthen only the external sphincter, improving voluntary control and potentially reducing incontinence symptoms 1
• Depression and anxiety are common after surgery, occurring in 6-16% of patients within 1-5 years post-operatively, and can affect perception of bowel control 3
• Supervised pelvic floor training is superior to unsupervised home programs for adherence and outcomes 1

Strengthening What Can Be Strengthened

Since only the external sphincter responds to voluntary training:

• Pelvic floor muscle training combined with aerobic and resistance exercise improves functional outcomes in post-surgical patients 1
• Weekly physiotherapy sessions with targeted pelvic floor exercises demonstrate measurable improvements in external sphincter function 1
• Institution-based or community-based programs with staff supervision show higher adherence than home-based programs 1

Addressing Psychological Factors

Your history of depression, anxiety, and fatigue requires integrated management:

• Cognitive behavioral therapy is first-line treatment for depression and anxiety in surgical patients, improving both psychological outcomes and physical functioning 1
• Fatigue and sleep disturbances are common in post-surgical patients with mental health conditions and must be addressed concurrently 1
• Coordinate care between physiotherapy, psychiatry/psychology, and primary care for optimal outcomes 1

Common Pitfall to Avoid

Do not assume that difficulty with bowel control means you need to "strengthen" your internal sphincter—this is physiologically impossible 1. Instead, focus on:

• Strengthening the external sphincter through proper pelvic floor exercises 1
• Addressing any underlying psychological factors that may amplify symptom perception 3, 1
• Ensuring adequate treatment of depression and anxiety, which can worsen quality of life and functional outcomes 3