Which are the cardinal movements during labor for vertex presentation?

The cardinal movements of labor for a vertex presentation describe the series of positional changes the fetus makes to progress through the birthing canal. The correct option outlines the complete sequence of these movements effectively.

The first movement is engagement, where the fetal presenting part enters the pelvic inlet. Following this, flexion occurs as the fetal chin moves toward the chest, which allows the smallest diameter of the fetal head to present to the pelvis. Descent refers to the downward movement of the fetus through the pelvis, which occurs progressively during labor.

Internal rotation is the next key movement, wherein the fetus rotates from a transverse position to an anterior or posterior position as it navigates the pelvic cavity. This rotation typically helps align the fetal head with the mother's pelvis. Extension then occurs as the fetal head emerges from the vagina, which implies the descent of the head while it is extending from the flexed position.

External rotation follows as the shoulders rotate to align with the pelvis, facilitating their descent. Finally, expulsion is the complete delivery of the fetus through the vaginal canal.

This sequence is significant because it represents a comprehensive view of how the fetus maneuvers during labor for a vertex presentation, ensuring that each movement contributes to a successful vaginal delivery while minimizing maternal and