Final answer:
The fetal presentation where buttocks appear first is called a breech presentation, which includes variations such as complete and frank breech. Most breech births are now delivered via Caesarean section.
Step-by-step explanation:
In a fetal presentation where the buttocks appear first, this is known as a breech presentation. There are several types of breech presentations, with the main ones being complete breech and frank breech. In a complete breech, both legs are crossed and the buttocks are positioned to deliver first, pointed downward. In a frank breech, the fetus' legs are extended upward towards the torso. Today, the majority of breech births are delivered by Caesarean section, a shift from the practice before the 1960s where vaginal delivery was common.