A woman undergoes a difficult forceps delivery. Postpartum she develops stress urinary incontinence and inability to voluntarily interrupt the urinary stream. Injury to which structure is the PRIMARY anatomical basis for her incontinence?

• A Pubocervical fascia alone
• B Arcuate pubic ligament
• C Round ligament of the uterus
• D Levator ani (especially the pubovisceral/pubococcygeus component) and its innervation ✓

Explanation

The levator ani — particularly the pubovisceral (pubococcygeus and puborectalis) part — forms the primary muscular support of the pelvic floor and compresses the urethra and anorectum during sudden rises in intra-abdominal pressure. Traumatic denervation or avulsion of levator ani during prolonged second-stage labour is the principal mechanism of post-obstetric stress urinary incontinence and inability to interrupt urine flow. The pudendal nerve (S2–S4), which supplies the external urethral sphincter, may also be stretched. Fascial injuries compound but are secondary to muscular damage.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.