Sequence of events in the normal mechanism of labour:
a. Engagement
b. Restitution
c. Internal rotation of head & shoulder
d. Crowning

1. A

   A, B, C, D

2. B

   A, C, D, B

3. C

   B, A, D, C

4. D

   C, B, D, A

Appeared in: MNS 2024

Explanation

• The correct sequence of the given events is Engagement (a), Internal rotation of head & shoulder (c), Crowning (d), and Restitution (b).
• Engagement is the first cardinal movement, where the fetal head's widest diameter enters the pelvic inlet.
• Internal rotation follows, where the head rotates to align with the pelvic outlet.
• Crowning occurs during the extension phase, when the largest diameter of the fetal head is visible at the vulva and does not retract between contractions.
• Restitution is the passive rotation of the delivered head to realign with the shoulders, which are still inside the pelvis.

Why Other Options Were Wrong

• Option A: This sequence (A, B, C, D) is incorrect because Restitution (b) occurs after the head is delivered (after Crowning, d), not before Internal Rotation (c).
• Option C: This sequence (B, A, D, C) is incorrect. It places Restitution (b) first and Engagement (a) second, which reverses the actual order. Engagement is an initial step, and Restitution is a final step.
• Option D: This sequence (C, B, D, A) is incorrect because Engagement (a) must occur before any other movements like Internal Rotation (c) or Crowning (d) can happen.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The concept tested is the sequence of cardinal movements during the normal mechanism of labor as background academic context rather than a clinical decision trigger.
• A thorough understanding of the mechanism of labor is crucial for nurses and midwives to accurately assess labor progress.
• Recognizing deviations from the normal sequence can help in the early identification of labor dystocia (abnormal labor), such as arrest of descent or rotation, which may indicate issues like cephalopelvic disproportion (CPD) or fetal malposition.
• Early detection of abnormalities allows for timely intervention, such as notifying the obstetrician, preparing for an assisted vaginal delivery, or anticipating a cesarean section, which is critical for maternal and fetal safety.

How to Approach the Question

• This is a process-based question that requires recalling a specific sequence of events.
• First, identify the four key events provided: (a) Engagement, (b) Restitution, (c) Internal rotation, and (d) Crowning.
• Recall the cardinal movements of labor. A helpful mnemonic is 'Every Darn Fetus Is Extremely Eager to Exit' (Engagement, Descent, Flexion, Internal Rotation, Extension, External Rotation/Restitution, Expulsion).
• Place the given events into this standard sequence:
• Engagement (a) is the first step.
• Internal rotation (c) comes after engagement.

Concept Tested & Keywords

• Concept Tested: The concept tested is the sequence of cardinal movements during the normal mechanism of labor.
• Stem keywords: Sequence of events, normal mechanism of labour
• Lead-in keywords: BEST, MOST RELEVANT CLUE

Question ID

Q71uI-J5eHDp7DZvNr4iyl

Copy ID

Reference Book

E6 Obstetrics Williams pp. 21-39, 20-36