Healthy Newborn with Cone Head and Patent Fontanelles
A slight cone head (caput succedaneum or molding) and patent fontanelles in a healthy newborn are completely normal findings that require no intervention. 1, 2
Normal Newborn Skull Anatomy
Patent (open) fontanelles are expected and normal in all newborns. The anterior fontanel averages 2.1 cm at birth and typically closes at a median of 13.8 months of age. 3
Cone-shaped head (molding) from vaginal delivery is a normal, self-resolving finding. This results from the skull bones overlapping during passage through the birth canal and typically resolves within days to weeks without treatment. 1
Head circumference measurements should be documented as part of routine newborn examination to establish a baseline for future monitoring. 1
When Patent Fontanelles Become Concerning
The fontanelles themselves are not concerning unless they demonstrate abnormal characteristics:
A bulging (tense) fontanel when the infant is upright and calm suggests increased intracranial pressure from meningitis, hydrocephalus, or intracranial bleeding—this requires immediate evaluation. 4, 3, 5
A sunken fontanel typically indicates dehydration and requires assessment of hydration status. 3
Abnormally large fontanelles (>3-4 cm) or delayed closure may suggest underlying conditions like hypothyroidism, Down syndrome, achondroplasia, or rickets—but this is assessed over months, not in the newborn period. 3
Widely patent fontanelles with rapidly increasing head circumference could indicate hydrocephalus or cerebral venous sinus thrombosis and warrants neuroimaging. 6
Clinical Assessment Approach
For a healthy newborn with normal fontanelles and physiologic molding, no imaging is indicated. 1, 2
Direct X-ray imaging is not indicated as routine examination for normal fontanelle findings. 1
Ultrasound through the fontanelle provides excellent visualization of the infant brain without radiation exposure if there are clinical concerns, but is unnecessary for normal findings. 2
Advanced imaging (CT/MRI) should be reserved only for cases where clinical examination reveals concerning findings such as bulging fontanelles, abnormal neurologic signs, or rapidly increasing head circumference. 1
Common Pitfall to Avoid
Do not confuse normal patent fontanelles with pathologic findings. The fontanelles should be soft and flat when the infant is calm and upright. Palpable suture lines and some degree of overriding of skull bones are normal in the immediate newborn period. 1, 3 The key is distinguishing normal anatomic variation from true bulging (which occurs with increased intracranial pressure) or abnormally wide fontanelles with other concerning features. 4, 5