A
cephalic presentation or
head presentation or
head-first presentation is a situation at
childbirth where the fetus is in a
longitudinal lie and the
head enters the pelvis first; the most common form of cephalic presentation is the vertex presentation where the
occiput is the leading part (the part that first enters the birth canal). All other presentations are abnormal (
malpresentations) which are either more difficult to deliver or not deliverable by natural means.