The relationship of skull change depends on which sutures are prematurely fused. Most commonly only one suture is involved. Premature fusion of the coronal suture leads to tall (turricephaly) or short AP skulls (brachycephaly, depending on whether you like describing the length or height of your skulls). Premature closure of the sagittal suture has the reverse effect leading to a long AP diameter and reduced height (so called scaphocephaly or dolicocephaly). Premature closure of the metopic suture causes trigoncephaly (forward pointing triangular skull) and plagiocephaly (side-ways skull) refers to the effects after unilateral or asymmetric closure of coronal and lamdoid sutures.
Normal width of the major sutures (Coronal, Sagittal and Lambdoid):
Wormian bones close by 6 months
Metopic suture (dividing frontal bone is usually closed by 2 years, but may persist as a normal variant)
Craniosynostosis may be primary (idiopathic) or secondary to a variety of endless aetiologies. Along with metabolic profiling and familial genetics, radiology is often central to the determination of the aetiology.
Secondary Causes of Craniosynostosis (non-exhaustive)
Metabolic (Rickets, Hypercalcaemia (and Hypervitaminosis D), Hyperthyroidism)
Haematological (Sickle Cell, Thalassaemia)
Dysplasia (Hypophosphatasia, Achondroplasia)
Syndromes (Hurler's, Apert's, Crouzon (similar to Apert but no syndactyly), Carpenter
Microcephaly (atrophy or dysgenesis)