Which mechanism of labor occurs when the largest diameter of the fetal presenting part passes the pelvic inlet?
A) Extension
B) Engagement
C) Internal rotation
D) External rotation

Question

Quizplus · Accepted Answer

Engagement occurs when the presenting part fully enters the pelvic inlet. Extension occurs when the fetal head meets resistance from the tissues of the pelvic floor and the fetal neck stops under the symphysis. This causes the fetal head to extend. Internal rotation occurs when the fetus enters the pelvic inlet. The rotation allows the longest fetal head diameter to conform to the longest diameter of the maternal pelvis. External rotation occurs after the birth of the head. The head then turns to the side so the shoulders can internally rotate and are positioned with their transverse diameter in the anteroposterior diameter of the pelvic outlet.

Which Mechanism of Labor Occurs When the Largest Diameter of the Fetal