SPONSORED VIDEO
Play Video
1
[MV] SKULL(스컬) _ I
[MV] SKULL(스컬) _ I'm getting married (결혼해요) (feat. Eugene(유진) of THE SEEYA)
::2014/07/17::
Play Video
2
Mystery Skulls Animated - Ghost
Mystery Skulls Animated - Ghost
::2014/10/27::
Play Video
3
skull bones
skull bones
::2008/10/25::
Play Video
4
Dr. Fabian Identifying Parts of the Skull Part 1 of 2
Dr. Fabian Identifying Parts of the Skull Part 1 of 2
::2008/10/16::
Play Video
5
[MV] SKULL(스컬) _ Ooh Baby
[MV] SKULL(스컬) _ Ooh Baby
::2014/08/20::
Play Video
6
Trick Art, Drawing  Levitating 3D Apple Skull
Trick Art, Drawing Levitating 3D Apple Skull
::2013/11/01::
Play Video
7
[MV] SKULL(스컬) _ DEH PON TOP
[MV] SKULL(스컬) _ DEH PON TOP
::2014/07/17::
Play Video
8
Skull - Cry Die
Skull - Cry Die
::2012/08/14::
Play Video
9
Half Skull Halloween Makeup Tutorial!
Half Skull Halloween Makeup Tutorial!
::2014/10/29::
Play Video
10
Steve Austin
Steve Austin's Broken Skull Challenge | Season 2 Episode 5 | Gods Of War
::2015/02/10::
Play Video
11
Steve Austin
Steve Austin's Broken Skull Challenge | Season 2 Episode 6 | Fallen On Hard Times
::2015/02/16::
Play Video
12
Halloween Skull Makeup - Chrisspy
Halloween Skull Makeup - Chrisspy
::2014/10/22::
Play Video
13
Monster High |Monster High Escape From Skull Shores|Monster High Full Movie
Monster High |Monster High Escape From Skull Shores|Monster High Full Movie
::2015/02/02::
Play Video
14
Röyksopp - Skulls (Official video)
Röyksopp - Skulls (Official video)
::2014/12/01::
Play Video
15
Show and Tell: Papercraft Skull Kit
Show and Tell: Papercraft Skull Kit
::2015/02/02::
Play Video
16
Lady Gaga Skull Makeup | Halloween Tutorial
Lady Gaga Skull Makeup | Halloween Tutorial
::2014/10/03::
Play Video
17
Steve Austin
Steve Austin's Broken Skull Challenge | Season 2 Episode 4 | Big Girls Dont Cry
::2015/01/27::
Play Video
18
Steve Austins Broken Skull Challenge s01e04 Boom or Bust
Steve Austins Broken Skull Challenge s01e04 Boom or Bust
::2015/01/16::
Play Video
19
Minecraft: HIDE THE GODZILLA SKULL - HIDE AND SEEK - Modded Mini-Game
Minecraft: HIDE THE GODZILLA SKULL - HIDE AND SEEK - Modded Mini-Game
::2015/02/02::
Play Video
20
Monster High Doll Show | Skull Academy | 129 Classes
Monster High Doll Show | Skull Academy | 129 Classes
::2015/01/18::
Play Video
21
[MV] SKULL(스컬) _ Because I was selfish(이기적인 놈이어서)
[MV] SKULL(스컬) _ Because I was selfish(이기적인 놈이어서)
::2014/08/31::
Play Video
22
Sculpting a Human Skull in Clay_part-1
Sculpting a Human Skull in Clay_part-1
::2011/05/16::
Play Video
23
Easy Sugar Skull | Day Of The Dead MakeUp Tutorial For Halloween
Easy Sugar Skull | Day Of The Dead MakeUp Tutorial For Halloween
::2014/10/01::
Play Video
24
스컬 (skull) / 하하 (haha) [REGGAErilla / Ragga Muffin] @SBS Inkigayo 인기가요 20130630
스컬 (skull) / 하하 (haha) [REGGAErilla / Ragga Muffin] @SBS Inkigayo 인기가요 20130630
::2013/07/01::
Play Video
25
スカル目玉焼き Skull Fried Eggs Bacon ハロウィーン Halloween ハロウィン
スカル目玉焼き Skull Fried Eggs Bacon ハロウィーン Halloween ハロウィン
::2014/10/25::
Play Video
26
SKULL Bande Annonce VF (Slasher - 2014)
SKULL Bande Annonce VF (Slasher - 2014)
::2014/02/13::
Play Video
27
Draw a Skull - Halloween Special
Draw a Skull - Halloween Special
::2013/10/31::
Play Video
28
RED SKULL VACILÃO #17
RED SKULL VACILÃO #17
::2015/02/16::
Play Video
29
Monster High Doll Show | Skull Academy 133
Monster High Doll Show | Skull Academy 133
::2015/02/21::
Play Video
30
Sugar Skull Makeup Tutorial ♡ Shaaanxo
Sugar Skull Makeup Tutorial ♡ Shaaanxo
::2014/10/12::
Play Video
31
Skull Fist  - Chasing The Dream - Full Álbum [2014]
Skull Fist - Chasing The Dream - Full Álbum [2014]
::2014/01/07::
Play Video
32
Monster High Doll Show | Skull Academy 132
Monster High Doll Show | Skull Academy 132
::2015/02/14::
Play Video
33
Monster High Doll Show | Skull Academy 131
Monster High Doll Show | Skull Academy 131
::2015/02/08::
Play Video
34
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::
Play Video
35
Monster High Doll Show | Skull Academy | 114 Lunch Room
Monster High Doll Show | Skull Academy | 114 Lunch Room
::2014/09/15::
Play Video
36
World
World's Largest Gummy Skull
::2013/06/20::
Play Video
37
Mystery of the Crystal Skulls - Documentary
Mystery of the Crystal Skulls - Documentary
::2013/08/10::
Play Video
38
Skull Makeup Tutorial 2014
Skull Makeup Tutorial 2014
::2014/02/27::
Play Video
39
How to Draw a Skull [White Pencil on Black Paper]
How to Draw a Skull [White Pencil on Black Paper]
::2014/11/01::
Play Video
40
Monster High Doll Show | Skull Academy 134
Monster High Doll Show | Skull Academy 134
::2015/02/21::
Play Video
41
GLAM SKULL • Makeup Tutorial
GLAM SKULL • Makeup Tutorial
::2014/10/21::
Play Video
42
RED SKULL VACILÃO #13
RED SKULL VACILÃO #13
::2014/11/15::
Play Video
43
Monster High Doll Show | Skull Academy | 130 Billy
Monster High Doll Show | Skull Academy | 130 Billy
::2015/01/25::
Play Video
44
Metal Gear Solid V - Skull Face Origins, Master Plan, & Analysis! (Ground Zeroes)
Metal Gear Solid V - Skull Face Origins, Master Plan, & Analysis! (Ground Zeroes)
::2014/04/02::
Play Video
45
Skull Found In Bonnie
Skull Found In Bonnie's Endoskeleton (Debunked) Five Nights at Freddy's 2 Theory
::2014/12/13::
Play Video
46
Halo 2 Anniversary - ALL Skulls, Terminals, & Toys in Order
Halo 2 Anniversary - ALL Skulls, Terminals, & Toys in Order
::2014/11/16::
Play Video
47
Monster High Doll Show | Skull Academy | 99 Fashion Show
Monster High Doll Show | Skull Academy | 99 Fashion Show
::2014/04/05::
Play Video
48
Town Hall 8 Skull Base - SPEDD BUILD Clash Of Clans
Town Hall 8 Skull Base - SPEDD BUILD Clash Of Clans
::2014/08/29::
Play Video
49
Easy Sugar Skull Halloween Tutorial
Easy Sugar Skull Halloween Tutorial
::2013/10/29::
Play Video
50
Sugar Skull Makeup Tutorial (800 RHINESTONES! ORIGINAL MADEULOOK!)
Sugar Skull Makeup Tutorial (800 RHINESTONES! ORIGINAL MADEULOOK!)
::2013/09/09::
NEXT >>
RESULTS [ .. ]
From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about the skulls of all animals including humans. For information specific to the human skull, see Human skull. For other uses, see Skull (disambiguation).
"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.[1] 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.[2]

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.[2]

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.[3]

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.[3]

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.[3]

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.[3] 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 diapsids, 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.[4]

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 
A horse skull 

References[edit]

  1. ^ http://www.merriam-webster.com/dictionary/skull
  2. ^ 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. 
  3. ^ 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. 
  4. ^ 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]

Wikipedia content is licensed under the GFDL License
Powered by YouTube
MASHPEDIA
LEGAL
  • Mashpedia © 2015