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[MV] SKULL(스컬) _ I
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::2014/07/17::
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スカル目玉焼き Skull Fried Eggs Bacon ハロウィーン Halloween ハロウィン
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Mariachi Sugar Skull - Makeup Tutorial!
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Sugar Skull Catrina Inspired Halloween Makeup Tutorial
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[MV] SKULL(스컬) _ Ooh Baby
::2014/08/20::
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skull bones
::2008/10/25::
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Lady Gaga Skull Makeup | Halloween Tutorial
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Halloween Skull Makeup - Chrisspy
::2014/10/21::
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Dr. Fabian Identifying Parts of the Skull Part 1 of 2
::2008/10/16::
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[MV] SKULL(스컬) _ Because I was selfish(이기적인 놈이어서)
[MV] SKULL(스컬) _ Because I was selfish(이기적인 놈이어서)
::2014/08/31::
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Skull - Cry Die
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Sugar skull tutorial I Halloween 2014
Sugar skull tutorial I Halloween 2014
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Sugar Skull Makeup Tutorial ♡ Shaaanxo
Sugar Skull Makeup Tutorial ♡ Shaaanxo
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[MV] SKULL(스컬) _ DEH PON TOP
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Day of the Dead Sugar Skull Halloween Makeup Tutorial
Day of the Dead Sugar Skull Halloween Makeup Tutorial
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Easy Sugar Skull | Day Of The Dead MakeUp Tutorial For Halloween
::2014/10/01::
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Draw a Skull - Halloween Special
Draw a Skull - Halloween Special
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::2013/07/01::
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Trick Art, Drawing Levitating 3D Apple Skull
::2013/11/01::
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Monster High Series | Skull Academy | 92 Tour
Monster High Series | Skull Academy | 92 Tour
::2014/01/30::
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Monster High Show | Skull Academy | 119 Ship
Monster High Show | Skull Academy | 119 Ship
::2014/10/25::
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Mold Making Tutorial: 1 Piece Gel-10 Skull Mold
Mold Making Tutorial: 1 Piece Gel-10 Skull Mold
::2013/09/27::
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23
Crush the Skull 2
Crush the Skull 2
::2013/10/31::
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Steve Austins Broken Skull Challenge - S01E01 - My Ranch My Rules - Full Show
Steve Austins Broken Skull Challenge - S01E01 - My Ranch My Rules - Full Show
::2014/07/19::
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EASY Sugar Skull Makeup Tutorial + DIY Flower Crown
EASY Sugar Skull Makeup Tutorial + DIY Flower Crown
::2014/10/25::
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Skulls Halloween makeup tutorial | ♥ Sugar skull ♥ | Lebkouni | Maska lebky
Skulls Halloween makeup tutorial | ♥ Sugar skull ♥ | Lebkouni | Maska lebky
::2014/10/21::
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steve austins broken skull challenge
steve austins broken skull challenge
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Steve Austins Broken Skull Challenge S01E02 Didnt Even Break a Nail
Steve Austins Broken Skull Challenge S01E02 Didnt Even Break a Nail
::2014/07/23::
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💀 Sugar Skull Smink Halloweenre/Farsangra 🌸
💀 Sugar Skull Smink Halloweenre/Farsangra 🌸
::2014/10/24::
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HALLOWEEN | Sugar Skull
HALLOWEEN | Sugar Skull
::2014/10/20::
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[Teaser 2] SKULL(스컬) _ Who gives a sh*t?(연예인이고 지랄이고)
[Teaser 2] SKULL(스컬) _ Who gives a sh*t?(연예인이고 지랄이고)
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Sugar Skull Halloween Tutorial ♡ Collab w/ AlliNicoleee and MakeupWithJah!
Sugar Skull Halloween Tutorial ♡ Collab w/ AlliNicoleee and MakeupWithJah!
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Steve Austins Broken Skull Challenge - S01E03 - Beards & Brawn - Full Show
Steve Austins Broken Skull Challenge - S01E03 - Beards & Brawn - Full Show
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Skull Makeup Halloween Tutorial | AHS Tate Inspired
Skull Makeup Halloween Tutorial | AHS Tate Inspired
::2014/10/20::
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Easy Sugar skull Makeup tutorial - Halloween 2014
Easy Sugar skull Makeup tutorial - Halloween 2014
::2014/10/14::
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The Grateful Dead - Grateful Dead (Album, Skull & Roses, October 24,1971)
The Grateful Dead - Grateful Dead (Album, Skull & Roses, October 24,1971)
::2013/09/06::
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Monster High Series | Skull Academy | 118 Sad Faces
Monster High Series | Skull Academy | 118 Sad Faces
::2014/10/18::
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How to make a SKULL PANCAKE (Pancake Art Tutorial)
How to make a SKULL PANCAKE (Pancake Art Tutorial)
::2014/09/22::
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MST3K   0912   The Screaming Skull
MST3K 0912 The Screaming Skull
::2012/11/04::
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Earth - The Bees Made Honey In The Lion
Earth - The Bees Made Honey In The Lion's Skull
::2013/03/18::
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Minecraft: SKULL ISLAND | NEW ADVENTURE, Ep.1
Minecraft: SKULL ISLAND | NEW ADVENTURE, Ep.1
::2013/08/27::
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GLAM SKULL • #SPOOKTOBER
GLAM SKULL • #SPOOKTOBER
::2014/10/21::
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New LoL Champion Teaser #2? Mysterious Fog and Skull Banner Video
New LoL Champion Teaser #2? Mysterious Fog and Skull Banner Video
::2014/10/23::
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Monster High Show | Skull Academy | 117 Cats
Monster High Show | Skull Academy | 117 Cats
::2014/10/11::
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SKULL HALLOWEEN MAKEUP
SKULL HALLOWEEN MAKEUP
::2014/09/12::
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Beautiful SUGAR SKULL Makeup Tutorial
Beautiful SUGAR SKULL Makeup Tutorial
::2014/10/06::
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47
Crush The Skull
Crush The Skull
::2011/10/30::
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48
Monster High Show | Skull Academy | 99 Fashion Show
Monster High Show | Skull Academy | 99 Fashion Show
::2014/04/05::
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49
Monster High Series | Skull Academy | 98 French
Monster High Series | Skull Academy | 98 French
::2014/03/28::
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50
Sugar Skull Makeup Tutorial (800 RHINESTONES! ORIGINAL MADEULOOK!)
Sugar Skull Makeup Tutorial (800 RHINESTONES! ORIGINAL MADEULOOK!)
::2013/09/09::
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From Wikipedia, the free encyclopedia
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This article is about the skulls of all animals including humans. For information specific to the human skull, see Human skull.
"cranium" and "crania" redirect here. For other uses, see cranium (disambiguation).

This article incorporates text from a public domain edition of Gray's Anatomy.

The skull is a bony structure in the head of most vertebrates (in particular, craniates) that supports the structures of the face and forms a protective cavity for the brain. The skull is composed of two parts: the cranium and the mandible. The skull forms the anterior most portion of the skeleton and is a product of encephalization, housing the brain, many sensory structures (eyes, ears, nasal cavity), and the feeding system.

Functions of the skull include protection of the brain, fixing the distance between the eyes to allow stereoscopic vision, and fixing the position of the ears to help the brain use auditory cues to judge direction and distance of sounds. In some animals, the skull also has a defensive function (e.g. horned ungulates); the frontal bone is where horns are mounted.

The English word "skull" is probably derived from Old Norse "skalli" meaning bald, while the Latin word cranium comes from the Greek root κρανίον (kranion).

The skull is made of a number of fused flat bones.

Fish skull[edit]

Fish head parts, 1889, Fauna of British India, Sir Francis Day

The skull of fishes is formed from a series of only loosely connected bones. Lampreys and sharks only possess a cartilaginous endocranium, with both the upper and lower jaws being separate elements. Bony fishes have additional dermal bone, forming a more or less coherent skull roof in lungfish and holost fish. The lower jaw defines a chin.

The simpler structure is found in jawless fish, in which the cranium is normally represented by a trough-like basket of cartilaginous elements only partially enclosing the brain, and associated with the capsules for the inner ears and the single nostril. Distinctively, these fish have no jaws.[1]

Cartilaginous fish, such as sharks and rays, have also simple, and presumably primitive, skull structures. The cranium is a single structure forming a case around the brain, enclosing the lower surface and the sides, but always at least partially open at the top as a large fontanelle. The most anterior part of the cranium includes a forward plate of cartilage, the rostrum, and capsules to enclose the olfactory organs. Behind these are the orbits, and then an additional pair of capsules enclosing the structure of the inner ear. Finally, the skull tapers towards the rear, where the foramen magnum lies immediately above a single condyle, articulating with the first vertebra. There are, in addition, at various points throughout the cranium, smaller foramina for the cranial nerves. The jaws consist of separate hoops of cartilage, almost always distinct from the cranium proper.[1]

Skull of an Atlantic wolffish

In ray-finned fishes, there has also been considerable modification from the primitive pattern. The roof of the skull is generally well formed, and although the exact relationship of its bones to those of tetrapods is unclear, they are usually given similar names for convenience. Other elements of the skull, however, may be reduced; there is little cheek region behind the enlarged orbits, and little, if any bone in between them. The upper jaw is often formed largely from the premaxilla, with the maxilla itself located further back, and an additional bone, the symplectic, linking the jaw to the rest of the cranium.[2]

Although the skulls of fossil lobe-finned fish resemble those of the early tetrapods, the same cannot be said of those of the living lungfishes. The skull roof is not fully formed, and consists of multiple, somewhat irregularly shaped bones with no direct relationship to those of tetrapods. The upper jaw is formed from the pterygoids and vomers alone, all of which bear teeth. Much of the skull is formed from cartilage, and its overall structure is reduced.[2]

Tetrapod skull[edit]

Skull of Tiktaalik, an extinct genus transitional between the lobe-finned fish and the early tetrapods. From the Late Devonian.

The skulls of the earliest tetrapods closely resembled those of their ancestors amongst the lobe-finned fishes. The skull roof is formed of a series of plate-like bones, including the maxilla, frontals, parietals, and lacrimals, among others. It is overlaying the endocranium, corresponding to the cartilaginous skull in sharks and rays. The various separate bones that compose the temporal bone of humans are also part of the skull roof series. A further plate composed of four pairs of bones forms the roof of the mouth; these include the vomer and palatine bones. The base of the cranium is formed from a ring of bones surrounding the foramen magnum and a median bone lying further forward; these are homologous with the occipital bone and parts of the sphenoid in mammals. Finally, the lower jaw is composed of multiple bones, only the most anterior of which (the dentary) is homologous with the mammalian mandible.[2]

In living tetrapods, a great many of the original bones have either disappeared, or fused into one another in various arrangements.

Fenestrae[edit]

Amphibians skulls, Hans Gadow, 1909 Amphibia and Reptiles
Scheme of Spinosaurus skull
A Centrosaurus skull

Living amphibians typically have greatly reduced skulls, with many of the bones either absent or wholly or partly replaced by cartilage.[2] In mammals and birds, in particular, modifications of the skull occurred to allow for the expansion of the brain. The fusion between the various bones is especially notable in birds, in which the individual structures may be difficult to identify.

The fenestrae in the skull of the dinosaur Massospondylus.

The fenestrae (from Latin, meaning windows) are openings in the skull.

Ceratopsian dinosaurs may have fenestrae in their frills.

Temporal fenestrae[edit]

The temporal fenestrae are anatomical features of the skulls of several types of amniotes, characterised by bilaterally symmetrical holes (fenestrae) in the temporal bone. Depending on the lineage of a given animal, two, one, or no pairs of temporal fenestrae may be present, above or below the postorbital and squamosal bones. The upper temporal fenestrae are also known as the supratemporal fenestrae, and the lower temporal fenestrae are also known as the infratemporal fenestrae. The presence and morphology of the temporal fenestra are critical for taxonomic classification of the synapsids, of which mammals are part.

Physiological speculation associates it with a rise in metabolic rates and an increase in jaw musculature. The earlier amniotes of the Carboniferous did not have temporal fenestrae but two more advanced lines did: the Synapsids (mammal-like reptiles) and the Diapsids (most reptiles and later birds). As time progressed, diapsids' and synapsids' temporal fenestrae became more modified and larger to make stronger bites and more jaw muscles. Dinosaurs, which are sauropsids, have large advanced openings, and their descendants, the birds, have temporal fenestrae which have been modified. Mammals, which are synapsids, possess no fenestral openings in the skull, as the trait has been modified. They do, though, still have the temporal orbit (which resembles an opening) and the temporal muscles. It is a hole in the head and is situated to the rear of the orbit behind the eye.

Classification[edit]

Chimpanzee skull

There are four types of amniote skull, classified by the number and location of their fenestra. These are:

  • Anapsida – no openings
  • Synapsida – one low opening (beneath the postorbital and squamosal bones)
  • Euryapsida – one high opening (above the postorbital and squamosal bones); euryapsids actually evolved from a diapsid configuration, losing their lower temporal fenestra.
  • Diapsida – two openings

Evolutionarily, they are related as follows:

Human skull[edit]

Model of a male human skull in the collections of the Museum of Osteology
For details and the constituent bones, see human skull, neurocranium and viscerocranium.

In humans, as in other mammals, the aforementioned division of the skull into the cranium and mandible is not usually followed. Instead, for the purposes of describing their anatomy and enumerating their bones, mammalian and human skulls are divided differently: They are deemed to consist of two categorical parts, the neurocranium and the viscerocranium. The neurocranium (or braincase) is a protective vault surrounding the brain. The viscerocranium (also splanchnocranium or facial skeleton) is formed by the bones supporting the face. Both parts have different embryological origins.

Except for the mandible, all of the bones of the skull are joined together by sutures, rigid articulations permitting very little movement.[3]

Bones[edit]

The jugal is a skull bone found in most reptiles, amphibians, and birds. In mammals, the jugal is often called the malar or zygomatic.

The prefrontal bone is a bone separating the lacrimal and frontal bones in many tetrapod skulls.

Terminology[edit]

Gallery[edit]

Paracyclotosaurus davidi skull, a prehistoric amphibian species 
Tyrannosaurus rex skull, a dinosaur species 
Alligator skull, a reptile species 
An elephant skull, a mammal species 
A lion skull 
A hippopotamus' skull 
Killer whale (Orcinus orca) skull 
A bulldog skull 
A Grizzly bear skull 
A coypu skull 
A gerbil skull 
A Four-horned antelope skull drawing 
Skull of a multi horned Jacob sheep 
A Vulture skull 

References[edit]

  1. ^ a b Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 173–177. ISBN 0-03-910284-X. 
  2. ^ a b c d Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 216–247. ISBN 0-03-910284-X. 
  3. ^ The hyoid bone and the ossicles are joined together with synarthroses, but despite their location, they are not normally considered skull bones.

External links[edit]

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