Normal full term baby has 6 fontanelle :
- Anterior
- Posterior
- 2 Mastoid
- 2 Sphenoidal
Posterior :
- Close at birth
- In only 3% it is open (here it just admits tip of finger)
Anterior :
- Diamond shape
- Open at birth
- 2.5 x 2.5 cm
- Pulsatile
- Closes at 18 - 24 months life.
Causes of Delayed closure of Anterior fontanelle :
- Down's Syndrome
- Hypothyroidism
- Hypophosphatasia
- Rickets
- Cleidocranial dysostosis
First four (1-4) and idiopathic are causes of delayed dentition. (Delayed dentition is non eruption of teeth by 13 months life )
Early closure of Anterior fontanelle : Craniosynostosis
Complications :
- Microcephaly
- Increased ICT - Optic atrophy
- Cosmetic - head shape (if only one suture fuses early)
Associated syndromes :
- APERT (AD)
- CROUZON (AD)
- CARPENTER - Autosomal recessive
- PFIFFER (AD)
Increased ICT : Anterior fontanelle - bulging & non pulsatile
Dehydration : Depressed Anterior fontanelle