Final answer:
The coronal suture is the joint that connects the frontal and parietal bones across the top of the skull. It is an essential part of the skull's structure, especially significant for the shape of the head.
Step-by-step explanation:
The joint that joins the frontal and parietal bones is known as the coronal suture. This joint runs from side to side across the top of the skull within the coronal plane and is a critical component of the skull's structure. The coronal suture is responsible for uniting the frontal bone with the right and left parietal bones, which form most of the upper lateral side of the skull. Each parietal bone is also bounded by other bones at different sutures such as the sagittal suture, lambdoid suture, and squamous suture, but the coronal suture's specific function is to connect the frontal bone to the parietals.
The visibility of sutures, like the coronal suture, can be of great importance in various fields such as forensic science and anthropology, where it helps in age estimation, identification, and understanding the biomechanics of the skull. Moreover, the sutures' integrity is vital in protecting the brain within the skull. The coronal suture is especially significant as it lies at the forefront of the skull and plays a key role in the overall shape and structure of the head.
Final answer: The coronal suture is the joint that unites the frontal bone with the right and left parietal bones across the top of the skull.