Microcephaly. Lateral X-ray (side view) of the head and skull of a 23-year-old patient with microcephaly. Microcephaly is a developmental disorder in which the brain fails to develop normally, resulting in a smaller than normal brain and head. Clinical features seen here include a posterior flattening of the bones of the cranium, a closed sella turcica (centre, the location of the pituitary gland), and hyperpneumatisation (enlargement) of the frontal sinus (upper right, in forehead).