Final answer:
Engagement of the presenting part normally occurs when the baby's head enters the pelvis in preparation for birth, and the most common delivery position is cephalic presentation. Breech presentation is less common and now Caesarian section is the usual delivery method for breech births.
Step-by-step explanation:
The engagement of the presenting part typically occurs when the baby's head moves into the pelvis in the lead-up to labor. The most common position for delivery is the cephalic presentation, where the baby's head is down and engaged with the cervix. However, in fewer than 5 percent of births, the baby is in a breech presentation, meaning the buttocks or feet are positioned to be delivered first. Of the breech presentations, a complete breech is where both legs are crossed and pointed downward, and a frank breech is where the legs are flexed at the hip and extended toward the shoulders. Historically, vaginal delivery was more common for breech births, but due to increased risks, Caesarian section is now the predominant method of delivery for breech presentations.