Final answer:
The incomplete closure of the frontal bone creates the metopic suture, which typically fuses within the first year after birth. Premature closure of this suture can lead to a form of craniosynostosis known as trigonocephaly, but if there's enough room for brain growth, it may not affect neurological development.
Step-by-step explanation:
The incomplete closure of the frontal bone creates the metopic suture or frontal suture. The metopic suture runs down the midline of the forehead towards the nose and is present at birth. It typically fuses within the first year after birth, but if it remains, it continues to be a persistent metopic suture. If the suture closes prematurely anomalously it can lead to a form of craniosynostosis known as trigonocephaly, where the forehead takes on a triangular shape. In primary craniosynostosis, the early fusion of one cranial suture can cause a compensatory abnormal enlargement in other regions of the skull. This can lead to various head deformities like scaphocephaly, but without neurological development complications if there’s enough room for brain growth. In cases where multiple sutures are involved, known as complex craniosynostosis, there are more severe constraints on skull growth potentially affecting brain development.