Anterior fontanelle is closed at

[Cl (12-18 months) Ref: 525, 1974-Nelson 17,h1. Anterior fontanelle: Formed by joining of four sutures in the midline, Diamond shape, 2 by 2 cm measurements* The floor is formed by membranous and it becomes ossified 18 month after birth. It becomes pathological, if it fails to ossify even after 24 months (84 - Dutta 6th)* The average time of closure is 18 months but the fontanel may normally close as early as 9 months. The fontanele is normally slightly depressed and pulsatile and is best evaluated when an infant is held upright while asleep or feeding (1974-Nelson 17th)Disorders associated with a large anterior fontanel* Achondroplasia* IUGR* Apert syndrome* Kenny syndrome* Athyrotic hypothyroidism* Osteogenesis imperfecta* Cleidocranial dysostosis* Prematurity* Congenital rubella syndrome* Pyknodysostosis* Hallermann-Streiff syndrome* Russell - Silver syndrome* Hydrocephaly* 13 - 18, 21 trisomies* Hypophosphatasia* Vitamin D deficiency ricketsPersistently small fontanels suggest microcephaly, cranio synostosis congenital hyperthyroidism or wormian bones2. Posterior fontanelle: between the intersection of the occipital and parietal bones that may be closed at birth or at the most admit the tip of finger. The posterior fontanele is usually closed and nonpalpable after the first 6- 8 weeks of life.Its persistence suggests underlying hydrocephalus or possibility of congenital hypothyroidism