The squamous suture is the connecting joint in the skull between the parietal bone and the lower portion of the temporal bone called the par squamosa. Edges of the squamous suture overlap in a scale-like formation. It is located just above the ears on both sides of the head. The two squamous sutures of the skull combine to form a half circle shape.
A squamous suture is classified as a joint even though the bones involved are not capable of movement. Anatomically, any point where two bones connect or meet is called a joint. It is a type of joint called a fibrous or synarthrosis joint. Collagen fibers develop after birth to bind the adjacent bones together. The squamous suture is only located in the joints of the skull.
This type of suture joint is one of the three types found on the skull. It is a lap suture, which indicates the overlap of the skull bones. Visually, it appears smooth and blended together, with small scale-like edges. They are unlike serrate sutures that have serrated edges, or plane sutures, which do not overlap or interlock, but instead are just flush next to the adjacent skull bone.
At birth the eventual location of the squamous suture is still open, and a small cavity marks the ultimate placement of the suture joint. As the infant grows, the collagen fibers that will close the opening begin to fill the space between the temporal and parietal bones. In time, the entire length of the joint will be sealed by the synarthrosis joint.
The squamous suture is a location used by neurologists to visualize the brainstem in newborns with suspected neurological disorders. Since it is not as developed in a newborn, it allows for the trans-anterior-fontanel nuerosonography (NS) equipment to obtain a good visual image of the brainstem. This test may be used in conjunction with a magnetic resonance imaging (MRI) test or a computerized tomography (CT) test to diagnose neurological problems. Early identification and treatment of a neurological disorder may help the infant achieve a greater degree of independence as an adult.
Some people undergo a squamous suture massage to release constriction in the dura mater near the joint. The temporal bone is gently massaged as the parietal bone is held in place. Therapeutic massage lasts for only a few minutes each session, and the goal is to release in the tension along the squamous suture.