All of the following muscles are cut during an episiotomy, except?

NORCET 2 - 2021 (shift-1)

Obstetrics & Gynaecology

Easy

Appeared in: NORCET 2 - 2021 (shift-1)

Explanation

The sphincter ani muscles (external and internal anal sphincters) are not intentionally incised during a standard episiotomy.
Cutting the anal sphincter is classified as a third- or fourth-degree perineal tear, which is a complication known as an Obstetric Anal Sphincter Injury (OASIS), not a planned surgical cut.
The goal of a mediolateral episiotomy is specifically to direct the incision away from the anal sphincter to prevent such injuries.
Inadvertent extension of a midline episiotomy or a poorly angled mediolateral episiotomy can lead to sphincter damage, which is associated with significant morbidity like fecal incontinence.

Option A: The superficial and deep transverse perineal muscles are located in the perineal body and are routinely incised during an episiotomy to enlarge the vaginal outlet.
Option C: The bulbospongiosus muscle is a superficial muscle of the perineum that overlies the vestibular bulb and is one of the primary muscles cut during an episiotomy.
Option D: While the entire levator ani muscle group is not transected, some of the most medial fibers (part of the pubococcygeus/pubovaginalis) are often involved in the incision, particularly in a deeper mediolateral episiotomy.

Visual 1: Diagram - An illustration of the female perineal anatomy, clearly labeling the bulbospongiosus, superficial and deep transverse perineal muscles, levator ani, and the external anal sphincter. This helps visualize the structures relative to the vagina and anus.
Visual 2: Diagram - A depiction of the two main types of episiotomy incisions (midline and mediolateral) overlaid on the perineal anatomy, showing which muscles are incised and how the mediolateral incision angles away from the anal sphincter.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the perineum and muscles involved in an episiotomy as background academic context rather than a clinical decision trigger.
Understanding the perineal anatomy is critical for nurses and midwives assisting with childbirth to anticipate, identify, and manage perineal trauma.
Postpartum nursing care involves assessing the episiotomy site for signs of healing, infection, or hematoma, and providing pain relief and hygiene instructions.
Patient education on perineal care after an episiotomy is a key nursing responsibility to promote healing and prevent complications.

How to Approach the Question

First, identify the core of the question: it asks for the muscle that is not cut during an episiotomy. The keyword 'except' is crucial.
Recall or look up the anatomy of the female perineum and the standard technique for an episiotomy, particularly the more common mediolateral type.
Systematically evaluate each option against your knowledge of the procedure.
Option A (Superficial & deep transverse perineal): These are central to the perineal body and are cut.
Option C (Bulbospongiosus): This is a superficial muscle that is cut.
Option D (Levator ani): Fibers of this muscle are often cut.

Concept Tested & Keywords

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