Cast of the Peking man skull, showing the keel continuing onto the frontal boneSagittal keel as seen in modern Homo sapiens
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 (notably the genus Paranthropus) 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.
Sagittal keels occur in several early human species, most noticeably in Homo erectus, occasionally in Homo heidelbergensis and in some Upper Paleolithic Homo sapiens specimens. Most modern Homo sapiens groups have lost them, likely as part of the general trend toward thinning of the cranial bones to make room for larger brains during the Pleistocene.[1] However, there is a small portion of modern humans who have the feature, but its function and etiology are unknown. Actor Patrick Stewart and the martial artist Shi Yan Ming present good examples of modern humans (Homo sapiens sapiens) with this feature. The keel appears to be tied to general cranial robustness and is more common in adult men than women and absent in children.
^Trevathan, Robert Jurmain, Lynn Kilgore, Wenda (2006). Introduction to physical anthropology (10th ed., Media ed.). Belmont, CA: Thomson/Wadsworth. ISBN 0-534-64422-8.{{cite book}}: CS1 maint: multiple names: authors list (link)
In the human skull, a sagittalkeel, or sagittal torus, is a thickening of part or all of the midline of the frontal bone, or parietal bones where they...
A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian...
over the ears, and connecting at the back of the skull, as well as a sagittalkeel running across the midline. The bone of the skull and long bones is...
these regions can be effectively dissipated across the skull; and the sagittalkeel protects the top of the braincase. Many skullcaps bear usually debilitating...
weakly-defined sagittalkeel that lacks a protuberance at the midpoint, unlike most other archaic humans. Unlike the Dali and Hualong Cave skulls, the keel does...
or top-wide skull of modern humans. It does however bear a prominent sagittalkeel, a trait found in H. erectus but in few modern humans. The brain appears...
Lantian Man has a heavy brow ridge, a receding forehead, possibly a sagittalkeel running across the midline of the skull, and exorbitantly thickened...
closely resemble earlier H. erectus. Like Peking Man, there was a slight sagittalkeel running across the midline of the skull. Compared to other Asian H. erectus...
skullcap (Trinil 2). Its characteristics were a long cranium with a sagittalkeel and heavy browridge. Dubois first gave them the name Anthropopithecus...
surfaces the neural canal is wide cranial caudals feature a ventral sagittalkeel, and their transverse processes are triangular-shaped in dorsal view...
The cranium is rather narrow, but long and tall, and with a clear sagittalkeel along the suture between the parietal bones. The face was large, both...
rostrum of Taniwhasaurus has a dorsal crest and the frontal bone has a sagittalkeel. The lateral margins of the frontal are straight. The genus also has...
early Homo such as H. habilis, including the well-developed brow ridge, sagittalkeels, large orbits, the premolar teeth in the upper jaw having single roots...
based on length-at-age estimates using annual and daily increments on sagittal otoliths". ICES Journal of Marine Science. 20 (6): 1128–1139. doi:10.1093/icesjms/fst039...
callosum Tractography of corpus callosum Corpus callosum with anatomography Sagittal post mortem section through the midline brain. The corpus callosum is the...
because both frontal bones have fused (craniosynostosis), it will cause a keel-shaped deformity of the skull called trigonocephaly. Its presence in a fetal...
Additionally, adult males have sharp canine teeth. Chimpanzees lack the prominent sagittal crest and associated head and neck musculature of gorillas. Chimpanzee...
proposed for the related genus Irritator, on account of the prominent sagittal crest running towards the back of its head. However, Evers and colleagues...
increased risk of fractures when exceeding about 3 mm. - LTC: lateral (or sagittal) tibial component angle, which is ideally positioned so that the tibia...
stability and support to the caudal fin, much like the keel of a ship. There may be a single paired keel, one on each side, or two pairs above and below. Finlets:...
lungs occupy the centre of some bones. The sternum is wide and usually has a keel and the caudal vertebrae are fused. There are no teeth and the narrow jaws...
it warrants its own genus. The skull was toothless and had a prominent sagittal crest, only the base of which was bony: the front of the crest featured...
Diplobune by the long and slender radius of the diaphysis plus constant sagittal diameter. The front area of the diaphysis has a clear and short edge for...
rostrally projecting bone. A prominent sagittal swelling is dominant on the midline of the parietal and forms a keel. The large, medial epiparietal is positioned...
hexagonal caputegulae form a sagittal midline row which terminate in an apex towards the rear and towards the sides of sagittal midline row is a row of both...
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