Fontanel last to close:-

FONTANELLE FORMED BY (BONES) SUTURE CLOSURE ADULT DERIVATIVE Anterior Fontanelle b/w frontal & parietal bones Bregma 1.5 - 2 years( Last to close) Bregma coronal with/withoutSagittal suture Posteriorfontanelle b/w parietal & occipital bones Lambdoid (may have Wormian bones) 2 - 3 months Lambda sagittal suture with lambdoid suture Posterolateral & mastoid fontanelle Parietal, occipital & temporal bones Asterion At 1 year Asterion Anterolateral & sphenoidal fontanelle Greater wing of sphenoidal frontal, parietal &temporal bones Pterion Upto 6 months Pterion (H-shaped) CLINICAL IMPOANCE 1. Fontanelles are sites of skull growth & helps to determine age 2. Anterior fontanelle used to assess intracranial pressure (bulging = |ICT; depressed = |ICP mostly 40 dehydration) 3. Bones override at the fontanelle helping to decrease size of the head during vaginal delivery