A<unk>  or head<unk>  or head-first<unk>  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<unk>  is the vertex<unk> , where the occiput is the leading part (the part that first enters the birth canal). All other<unk> s are abnormal (malpresentations) and are either more difficult to deliver or not deliverable by natural means.
Cephalic presentation
Non-lifting sign
Shoulder presentation
Dysmorphic feature
Thrifty phenotype
Multiple abnormalities
Vertical auto profile
Triangular face