An Overview of the Squamous Suture

There are five major joints, or sutures, that connect the bones in your skull. These flexible joints allow the bones in the skull to accommodate brain growth during infancy.

The squamous suture is of particular importance because it connects the parietal bones, which form the roof and sides of the skull, to the temporal bones, which form the side and base of the skull.

Anatomy of the Skull

An infant’s skull is made up of bony plates, sutures, and fontanelles, which all work together to protect the brain and allow it room to grow. The sutures act as flexible joints that allow the skull to mold during birth. They also allow the brain to grow during infancy. 

The fontanelles in your baby’s skull, often known as “soft spots,” are located in the spaces between the bones where the sutures intersect. These open spaces are covered with tough membranes to protect your baby’s brain.

The anterior fontanelle is located on the top of the head where the two frontal bones and two parietal bones meet. This fontanelle stays open until your little one’s second birthday. The posterior fontanelle is located toward the back of your baby’s skull where the two parietal bones meet the occipital bone. This fontanelle is usually the first to close. 

The Skull’s Five Sutures

The squamous suture runs along the side of the face, connecting the parietal bones to the temporal bones on each side of the head.

In addition to the squamous suture, the other major sutures in an infant’s skull include:

• Coronal suture: The coronal suture runs from ear to ear over the top of the head. It connects both frontal bones to the parietal bones.
• Sagittal suture: The sagittal suture runs from the top of the head to the back of the head. It joins the two parietal bones together. 
• Metopic suture: The metopic suture runs from the top of the nose up to the top of the head. It connects the two frontal bones together.
• Lambdoid suture: The lambdoid suture runs across the back of the head. It joins both parietal bones to the occipital bone in the back of the skull. 

The Significance of the Squamous Suture in the Skull

The sutures are responsible for connecting the skull bones together before they fuse. When your baby is born, the flexible sutures allow them to make their way through the birth canal. During labor and birth, the sutures allow the skull bones to overlap on top of one another to fit through the birth canal. This protects the brain from being pressed on and damaged.

The squamous suture acts as an expansion joint between the parietal and temporal bones. As the brain grows during infancy, the sutures allow the skull to grow and expand. If the skull was not able to expand during infancy, your little one’s brain would start to press against the hard bones. This would lead to increased pressure on the brain and possibly brain damage. 

It is possible for the squamous suture to fuse prematurely, causing the bones to join and harden. This condition is known as craniosynostosis. Squamous craniosynostosis is not common, and may occur as part of a genetic disorder. 

Suture Strain: What to Look For

Suture strain refers to times when the sutures in an infant’s skull are put under pressure or strain. This could happen during trauma to the skull or from an underlying condition that causes increased pressure on the brain, known as increased intracranial pressure.

When pressure builds up in an infant’s skull, the sutures naturally stretch to accommodate for the increased pressure. This adaptation puts them under strain. 

To help determine if your little one is experiencing suture strain, it is helpful to know the signs of increased intracranial pressure. First, assess your baby’s anterior fontanelle on the top of the head. If it appears to be bulging up, this could indicate increased pressure in the skull.

Other signs of increased intracranial pressure in newborns and infants include:

• Irritability
• Vomiting
• Sleepiness 
• Keeping eyes down all the time

Increased intracranial pressure is a medical emergency and requires treatment right away. 

Summary

Sutures are flexible structures that allow your baby's head to pass through the birth canal and room for their brain to grow during infancy. The squamous suture connects the parietal bones, which form part of the side and top of the skull, to the temporal bones, which form part of the side and the bottom of the skull. A condition called craniosynostosis can cause sutures to fuse prematurely, increasing pressure in your baby's brain. Increased intracranial pressure requires treatment right away.

A Word From Verywell

The bones, sutures, and fontanelles in your baby’s skull work together expertly to protect their brain and allow room for normal brain growth. The squamous sutures are flexible joints that connect an infant’s parietal bones to their temporal bones on each side of the face. 

If you notice any changes to your child’s head or skull shape, talk with your doctor right away. Any signs of increased intracranial pressure, such as a bulging fontanelle, require immediate treatment. 

Frequently Asked Questions

Are the squamosal suture and squamous suture the same thing? 

Yes, the terms “squamosal suture” and “squamous suture” both refer to the same suture that connects the temporal and parietal bones in the skull.