Plagiocephaly occurs the most often. It happens in approximately 1 out of 2500 births. It involves fusion of either the right or left side of the coronal or lambdoid suture. This is called coronal (or lambdoid) synostosis and it causes the normal forehead and brow to stop growing. Therefore, it produces a flattening of the forehead and the brow on the affected side, with the forehead tending to be excessively prominent on the opposite side. There may also be flattening of the back (occipital) area. The eye on the affected side may also have a different shape.

Trigonocephaly is a fusion of the metopic (forehead) suture. This suture runs from the top of the head down the middle of the forehead, toward the nose. Early closure of this suture may result in a prominent ridge running down the forehead. Sometimes the forehead looks quite pointed, like a triangle, with closely placed eyes (hypotelorism).

Scaphocephaly is an early closure or fusion of the sagittal suture. This suture runs front to back, down the middle of the top of the head. This fusion causes a long, narrow skull. The skull is long from front to back and narrow from ear to ear.