The skull's superior view is dominated by the frontal and parietal bones. The frontal bone forms the forehead with thick supraorbital margins and foramina lying under the eyebrows. In between the margins is the glabella, a smooth region. The frontal bone meets the paired parietal bones at the coronal suture. These paired parietal bones, covering the skull's top and sides, are joined by the sagittal suture. Forming the posterior part and most of the base of the skull is the occipital bone. It connects to the parietal bones via the lambdoid suture. A midline projection, the external occipital protuberance, secures a large elastic ligament — ligamentum nuchae, which helps support the head. The superior and inferior nuchal lines are laterally extending ridges that allow muscle attachment. At the base, through the opening called the foramen magnum, the brain connects with the spinal cord. On each side of the foramen, the occipital condyles, curved projections, articulate with the first vertebra.