Final answer:
The sagittal suture is the immobile joint located on the top of the head between the pair of parietal bones, part of a system of sutures that provide structural support and protection for the brain.
Step-by-step explanation:
The suture on top of the head between the two parietal bones is known as the sagittal suture. This suture line extends from the coronal suture, which runs across the top of the skull in the coronal plane and unites the frontal bone to the right and left parietal bones, to the posterior skull where it concludes by joining the lambdoid suture. The lambdoid suture, which has an inverted 'V' shape, connects the occipital bone with the parietal and temporal bones. Additionally, on the lateral side of the skull, the pterion, an H-shaped suture junction area, unites four different bones: the frontal bone, parietal bone, squamous portion of the temporal bone, and sphenoid bone.
Sutures are immobile joints that are located between the bones of the skull, filled with dense, fibrous connective tissue that forms a tight interlocking boundary between bones, adding structural integrity and protection for the brain.