In the human skull, a sagittal keel, or sagittal torus, is a thickening of part or all of the midline of the frontal bone, or parietal bones where they meet along the sagittal suture, or on both bones. Sagittal keels differ from sagittal crests, which are found in some earlier hominins and in a range of other mammals. While a proper crest functions in anchoring the muscles of mastication to the cranium, the keel is lower and rounded in cross-section, and the jaw muscles do not attach to it.