What symptoms does an over‑stretched (lax) puborectalis muscle cause in men?

Symptoms of Over-Stretched Puborectalis Muscle in Men

An over-stretched (lax) puborectalis muscle in men primarily causes fecal incontinence, obstructive defecation symptoms (straining, incomplete evacuation), sexual dysfunction (reduced sensation during intercourse, erectile difficulties), and urinary symptoms (urgency, incomplete bladder emptying). 1

Primary Symptom Clusters

Bowel Dysfunction

• Fecal incontinence is the hallmark symptom when puborectalis laxity combines with reduced internal anal sphincter tone, though muscle weakness alone does not always cause incontinence 2
• Obstructive defecation manifests as excessive straining, sensation of incomplete evacuation, and need for digital assistance during bowel movements 1
• The paradox of both incontinence and constipation can coexist because the stretched muscle loses both its continence-maintaining angle and its ability to relax properly during defecation 2

Urogenital Symptoms

• Sexual dysfunction including reduced genital sensation, erectile difficulties, and impaired orgasmic function may persist even when other symptoms improve 1
• Urinary symptoms can include urgency, frequency, incomplete bladder emptying, and reduced bladder/urethral sensation when pudendal nerve stretch injury accompanies the muscle laxity 1
• Post-void residual volumes may be elevated due to associated pelvic floor denervation affecting bladder contractility 3

Physical Examination Findings

• Excessive perineal descent (>3 cm during straining) is the mechanical hallmark of chronic puborectalis over-stretching 1
• Patulous (gaping) anal opening during simulated defecation indicates neurogenic dysfunction of the external anal sphincter from associated pudendal nerve injury 1
• Deviation of the anus away from the side of muscle rupture or severe laxity may be visible on inspection 4
• The anorectal angle widens excessively (>118 degrees) during straining, losing the normal continence-maintaining acute angle 5

Underlying Mechanism

The puborectalis muscle becomes over-stretched through chronic straining (descending perineum syndrome), which causes traction injury to the distal branches of the pudendal nerve that innervate both the muscle and the pelvic floor 2, 6. This creates a vicious cycle: denervation weakens the muscle, leading to more descent and further nerve stretch 2. In men, this typically occurs from chronic constipation, heavy lifting, or pelvic trauma 1.

Critical Diagnostic Pitfalls

• A normal anal reflex does NOT exclude puborectalis dysfunction because superficial sensory pathways may remain intact while deeper motor pathways supplied by the pudendal nerve are impaired 1
• Normal mean pudendal nerve terminal motor latency (PNTML) does NOT rule out pudendal neuropathy—each side must be evaluated separately because unilateral prolongation is missed when only the average is reported 1
• Acute tenderness over the puborectalis indicates levator ani syndrome, not chronic stretch injury, and represents a completely different condition requiring different management 1

Associated Findings

• Pelvic floor muscle dysfunction is present in 80% of men even without symptoms, so the absence of complaints does not indicate normal muscle function 7
• The puborectalis shows both more frequent and more severe dysfunction than the external anal sphincter in population studies 7
• No clear dose-response relationship exists between the degree of muscle dysfunction and the number of symptoms reported 7

When to Suspect This Diagnosis

Suspect puborectalis over-stretching in men presenting with:

• Combined fecal incontinence and constipation symptoms 2
• Sexual dysfunction (especially reduced sensation) with bowel or bladder symptoms 1
• History of chronic straining, heavy lifting, or pelvic surgery 6
• Visible perineal descent or anal deviation on examination 1, 4