Can the puborectalis muscle be accidentally overstretched or damaged?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: February 27, 2026 • View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Can the Puborectalis Muscle Be Accidentally Overstretched or Damaged?

Yes, the puborectalis muscle can be accidentally overstretched or damaged through multiple mechanisms, most commonly during vaginal delivery, chronic straining, and iatrogenic surgical injury.

Primary Mechanisms of Injury

Obstetric Trauma

  • Vaginal delivery causes direct structural damage through extreme tissue stretching, with up to 19% of first-time mothers experiencing levator ani muscle injury and avulsion. 1
  • Women with levator ani avulsion (which includes the puborectalis as part of the levator ani complex) face a 7.3 odds ratio for developing pelvic organ prolapse later in life. 1
  • Instrumental delivery (forceps or vacuum) amplifies tissue damage risk, and prolonged first or second stages of labor increase the likelihood of intervention and subsequent injury. 1
  • The pudendal nerve, which supplies the external anal sphincter and runs in close proximity to the puborectalis, can be stretched during delivery, causing pudendal neuropathy that manifests as sphincter weakness and incontinence. 2

Chronic Straining Injury

  • Excessive straining during defecation causes perineal descent greater than 3 cm, which stretches the pudendal nerve and can lead to progressive neuropathy. 3
  • Chronic increased intra-abdominal pressure from conditions like chronic constipation or obesity leads to chronic overstraining that damages pelvic floor structures over time. 1
  • Pudendal nerve stretch injury from chronic straining results in denervation of both the external anal sphincter and contributes to puborectalis dysfunction. 2

Iatrogenic Surgical Damage

  • Intersphincteric dissections for low rectal cancer and fistula surgery involving the intersphincteric space place the inferior rectal branches of the pudendal nerve at direct risk of transection. 4
  • Debridement of lower sacral segments (below S3/S4) during pelvic osteomyelitis treatment can damage the S2-S4 nerve roots that innervate the external anal sphincter and puborectalis, resulting in permanent fecal incontinence. 4
  • Manual anal dilatation causes permanent incontinence in 10-30% of patients and is absolutely contraindicated because it tears the internal sphincter and stretches the puborectalis beyond its elastic limit. 4

Clinical Consequences of Injury

Functional Impairment

  • Puborectalis damage disrupts the anorectal angle maintenance mechanism, which is integral to continence. 2
  • The muscle's nerve supply is independent of the anal sphincters, so isolated puborectalis injury can occur without sphincter damage. 2
  • Pudendal neuropathy diminishes rectal sensation and leads to excessive stool accumulation, causing fecal impaction and overflow incontinence. 2

Delayed Presentation Pattern

  • Most women who sustain obstetric injury in their 20s or 30s do not present with fecal incontinence until their 50s, suggesting a progressive denervation process compounded by aging and hormonal changes. 2
  • Estrogen deficiency at menopause negatively impacts pelvic floor integrity, unmasking previously compensated injuries. 1
  • Approximately 25-33% of postmenopausal women develop pelvic organ prolapse, with an 11% lifetime risk of requiring surgical intervention by age 80. 1

Diagnostic Approach for Suspected Injury

Physical Examination

  • Digital rectal examination should assess resting tone (internal sphincter) and squeeze augmentation (external sphincter and puborectalis), with observation of perineal descent during simulated defecation. 4
  • Perineal descent greater than 3 cm during straining suggests chronic nerve stretch injury. 3
  • A patulous (gaping) anal opening during simulated defecation strongly indicates neurogenic dysfunction. 3

Objective Testing

  • Anorectal manometry is the first-line test to quantify sphincter pressures and identify paradoxical contraction patterns. 4
  • Pudendal nerve terminal motor latency (PNTML) testing must evaluate each side separately, as unilateral prolongation is missed when only the average is reported. 3
  • 3D anal ultrasonography or MRI identifies structural defects, muscle atrophy, or complete avulsions. 4

Critical Clinical Pitfall

A normal digital rectal examination does NOT rule out pelvic floor dysfunction or puborectalis injury; objective testing with manometry and imaging should be pursued when clinical suspicion remains high. 4, 3

References

1
Guideline

Pelvic Floor Muscle Weakness in Women

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

2
Research

Pathophysiology of adult fecal incontinence.

Gastroenterology, 2004

3
Guideline

Pudendal Neuropathy Diagnosis and Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

4
Guideline

Nerve Supply and Dysfunction of the Anal Sphincter

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Related Questions

Can the external anal sphincter and puborectalis be trained to relax when they are compensating for reduced internal anal sphincter tone in an adult male, and is that compensation necessary for continence?
Can sarcoidosis cause fecal incontinence?
What are the causes of fecal incontinence?
What are the causes and management options for urinary and fecal incontinence?
Can a single episode of severe constipation trigger persistent paradoxical puborectalis contraction, pelvic‑floor hypertonicity, and dyspareunia?
For a sexually active adult (any gender) with a positive high‑risk HPV DNA test for types 18 and 45, what are the recommended next steps in evaluation and management?
Is baseline laboratory testing required before starting topical terbinafine for localized tinea cruris in a healthy adult?
Should I use sunscreen with Epiduo (adapalene 0.1%/benzoyl peroxide 2.5%) and what type and frequency is recommended?
What is the recommended protocol for diagnosing and treating ocular tuberculosis?
What is the recommended antimicrobial regimen and duration for a patient with a confirmed non‑bacteremic carbapenem‑resistant Acinetobacter baumannii infection?
What are the indications, preferred agents, and recommended duration of dual antiplatelet therapy in adults with coronary artery disease after acute coronary syndrome or percutaneous coronary intervention (including stent type and bleeding risk)?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question