The posterior fontanelle (lambdoid fontanelle, occipital fontanelle) is a gap between bones in the human skull (known as fontanelle), triangular in form and situated at the junction of the sagittal suture and lambdoidal suture. It generally closes in 6–8 weeks from birth. The cranial point in adults corresponding the fontanelle is called lambda. A delay in closure is associated with congenital hypothyroidism.

Posterior fontanelle
Skull at birth, showing frontal and occipital fonticuli
Details
Identifiers
Latin	fonticulus posterior
TA98	A02.1.00.029
TA2	433
FMA	75440
Anatomical terminology [edit on Wikidata]