Class Notes.docx

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Metopic suture. This extends from the top of the head down the middle of the forehead, toward the nose. The 2 frontal bone plates meet at the metopic suture.

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Coronal suture. This extends from ear to ear. Each frontal bone plate meets with a parietal bone plate at the coronal suture.

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Sagittal suture. This extends from the front of the head to the back, down the middle of the top of the head. The 2 parietal bone plates meet at the sagittal suture.

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Lambdoid suture. This extends across the back of the head. Each parietal bone plate meets the occipital bone plate at the lambdoid suture. Sutures allow the bones to move during the birth process. They act like an expansion joint, allowing the bone to enlarge evenly as the brain grows and the skull expands, resulting in a symmetrically shaped head. However, if any of the sutures close too early (fuse prematurely), there may be no growth in that area. This may force growth to occur in another area or direction, resulting in an abnormal head shape.

What are fontanelles?

There are 2 fontanelles (the space between the bones of an infant's skull where the sutures intersect) that are covered by tough membranes that protect the underlying soft tissues and brain. The fontanelles include: 

Anterior fontanelle (also called soft spot). This is the junction where the 2 frontal and 2 parietal bones meet. The anterior fontanelle remains soft until about 18 months to 2 years of age.

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Posterior fontanelle. This is the junction of the 2 parietal bones and the occipital bone. The posterior fontanelle usually closes first, before the anterior fontanelle, during the first several months of an infant's life.