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skull

  (skŭl)

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skull

lateral view of an adult human skull (Carlyn Iverson)

1. The bony or cartilaginous framework of the head of vertebrates, made up of the bones of the braincase and face; cranium.
2. Informal. The head, regarded as the seat of thought or intelligence: Use your skull and solve the problem.
3. A death's-head.

[Middle English skulle, probably of Scandinavian origin.]

The human skull has been rich in symbolism over the course of Western history. The skull as an emblem of death appeared as a result of the casualties brought on by the bubonic plague or the Black Death that ravaged the inhabitants of Europe throughout the fourteenth and fifteenth centuries. The Dance of Death, which portrayed men and women of all classes dancing with a skeleton, became a popular artistic motif.

The skull as an intimation of death was also an obvious aspect of sixteenth-century century fashion and art. In the early decades of the century, portraits had skulls printed on the back in order to symbolize the inevitable demise of the sitter. Men and women of the upper classes wore medallions engraved with skulls and ivory heads as jewelry. These objects normally portrayed a living face on one side and the human skull on the other side. The mementos were to remind both the wearer and the onlooker of death and their obligation to lead moral lives. The keepsakes also revealed the tension experienced by members of the upper classes who desired to display their wealth while appearing to obey the dictates of Christian piety.

In the eighteenth century, Caribbean pirates flew flags that featured the human skull and crossbones. The symbol, known as the Jolly Roger, may have been a corruption of joli rouge (pretty red), the original colour of the flag. The phrase also may have referred to a pirate known as ‘Ali Raja’ or simply have designated the British term for devil, vagabond, and rogue. The eighteenth-century French pirate Emanuel Wynne was the first to use the skull and crossbones. Wynne also displayed an hourglass on his flag to indicate that time was running out for his intended victims.

In the twentieth century, the Nazi SS adopted the human skull and crossbones, called Death's Head, as the badge of their organization. The Totenkopfverbande, or ‘Death's Head units’, were among the most élite and most feared members of the SS. Taking their name from the death's head symbol they wore on the right collar of their uniform, the Totenkopfverbande initially guarded concentration camps, but their role was expanded to include military service, most prominently in Poland and the Soviet Union, where they were responsible for killing Jews, soldiers, and civilians.

The human skull and crossbones have not simply been the mark of infamous men and women; more significantly, they have warned young and old alike of the dangers posed by poisons, toxins, and other hazardous materials. The poison symbol is successful because it is easily identifiable and can be understood by those who are unable to read.

Finally, the human skull figured in nineteenth-century scientific debates, especially those that concerned the attributes of the various races. Practitioners of craniometry, or the science of measuring skulls, maintained that they possessed empirical evidence that showed the superiority of Caucasians over other races. Nineteenth-century criminal anthropologist Cesare Lombroso employed craniometry to bolster his claim that criminals possessed an innate predilection to commit crimes. Lombroso said large jaws, low and narrow foreheads, and smaller cranial capacity were characteristics of natural-born criminals.

(a) Adult skull showing the main bones that can be seen from the front. (For side view see -->craniometry-->.) (b) The skull at birth. Note the relatively large size of the neurocranium. Most of the enlargement of the skull occurs in early childhood: the greatest increase in size (about two-thirds) occurs in the first two years

Structure and evolution

Anatomically, the adult cranium is an extremely complex region of the skeleton. It comprises some 27 bones, forming two components, — the neurocranium (brainbox) and the splanchnocranium (face). The neurocranium consists of a base and vault whose side walls and roof complete the protective encasing around the delicate brain. The splanchnocranium houses and protects many of the organs of special sense — sight, smell, and taste — as well as accommodating the first part of both the respiratory and alimentary tracts. The upper part of this face-skeleton forms the orbits and nose, whilst the lower part, together with the mandible, forms the jaws. The face is probably the most expressive aspect of human anatomy and this is made possible by more than 50 muscles that attach to the underlying skull. Despite the mobility which these provide, with the exception of the small bones of the middle ear there are only two moving joints in the entire face region, and even they cannot move independently, as the two sides must work in unison. The free movement of the jaw at these temporomandibular joints is critical to the success of both phonation (speech) and mastication (chewing). In historical times, infection of the joint could lead to ankylosis (fusion), which was obviously not compatible with sustained life.

The skull is probably the region of the human body that is most avidly studied with respect to human evolution. The size of the neurocranium and its size relative to the splanchnocranium have been critical to the definition of the hominid lineage. The apes tend to possess a relatively smaller neurocranium and larger face than modern man and his immediate ancestors. The modern human face is suspended under the brain, having rotated backwards and downwards underneath the neurocranium, whilst the brain has extended above and over the top of the face, giving modern man his characteristically high forehead that protects the frontal lobes of the brain.

Development and growth

In the child, the neurocranium develops in parallel with the early maturation of the central nervous system, whilst the splanchnocranium lags behind and is more closely linked to the development of the teeth. Hence the ‘cutesy’ and non-threatening appeal of baby cartoon characters with big eyes, a big head, and a small face. This early development of the brain along with its protective case has enormous implications with regard to the evolution of man and encephalization in particular. This is the study of the degree to which the nervous system of the human fetus matures in utero. Compared with all other animals, including other primates, human babies are born with relatively big heads that house a large brain. During the early part of this century, before Caesarean sections were commonplace or indeed safe, pelvimetry (measurements of the maternal pelvis) was frequently employed in an attempt to predict the outcome of labour. Cephalopelvic disproportion — when the baby's head was too large to pass successfully through the birth canal — was a serious clinical concern, as it led to high levels of fetomaternal mortality. However, to overcome this transitory problem, the fetal skull retains considerable flexibility, as the bones are not fully formed and so can ride over each other as the head passes down through the birth canal. It is whimsical to suppose that perhaps new-born babies cry because they start life with a blinding headache!

Forensic applications

In physical and forensic anthropology, the skull is extremely informative with regard to the identification of sex, age at death, and racial assignation. It also plays a pivotal role in establishing the identity of the deceased — it has been described as the ‘bony core of the fleshy head and face’. There are various techniques available to the forensic investigator in this context. To confirm or reject a proposed identity, the skull of the deceased can be compared with a portrait or photograph of the person during life; the image of the skull, live on camera, is superimposed on the static photograph until the correct sizing and orientation are achieved. Then, using specific anatomical landmarks, the ‘degree of fit’ of the two images can be assessed. When the identity is entirely unknown, facial reconstruction is employed. This can be achieved either by computerized methods, where a standard face is wrapped around the scanned image of the skull, or alternatively by clay modelling. The latter approach requires a considerable degree of skill and generally leads to a more realistic image of the deceased. The function of facial reconstruction is not necessarily to produce a near-photographic image of the deceased, but more realistically to strike a chord with family or friends of a missing person. Such was the case of a young man who was found on the top of a Scottish mountain. He had been dead for nearly two years when he was found accidentally by two climbers. Investigations by the local police did not lead to any success in his identification and so it was decided to reconstruct his face. The outcome was shown on the television programme Crimewatch and was picked up by its French television counterpart. It was recognized by a French family who knew that their son had gone walking in Scotland before he went missing, but whose own investigations had been unsuccessful. A simple DNA test confirmed his identity. Such is the way, in osteology, that the dry bones have, of coming back to life to tell their own story.

— Karol K. Weaver, Sue M. Black

Bibliography

• Aiello, L. and Dean, C. D. (1990). An introduction to human evolutionary anatomy. Academic Press, London.
• Cohen, K. (1973). Metamorphosis of a death symbol: the transi tomb in the late Middle Ages and the Renaissance. University of California Press, Berkeley.
• Davies, J. D. (1955). Phrenology fad and science: a nineteenth-century American crusade. Yale University Press, New Haven.
• Reichs, K. J. (1998). Forensic osteology: advances in the identification of human remains, (2nd edn). CC Thomas, Springfield, Illinois.
• Scheuer, J. L. and Black, S. M. (2000). Developmental juvenile osteology. Academic Press

See also anthropology; craniometry; evolution; phrenology; skeleton; skull-shaping.

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Front and side views of the human skull. (credit: © Merriam-Webster Inc.)

Skeletal framework of the head. With the exception of the lower jaw, its bones meet in immovable joints (sutures) to form a unit that encloses and protects the brain and sense organs and gives shape to the face. The cranium, the upper part enclosing the brain, comprising the frontal, parietal, occipital, temporal, sphenoid, and ethmoid bones, is globular and relatively large compared to the facial portion. Its base has an opening through which the spinal cord connects to the brain. The skull sits on the top vertebra (atlas), which permits back-and-forth motion. For side-to-side motion, the atlas turns on the next vertebra (axis). See also craniosynostosis, fontanel.

For more information on skull, visit Britannica.com.

Several farms and manor houses formerly kept a skull on display, allegedly that of someone who had lived there and had insisted that this be done; the luck of the house and family was said to depend on its presence, and if anyone tried to remove or bury it, it would either return of its own accord, or cause violent and noisy haunting until replaced. There were examples at Wardley Hall, Osbaldeston Hall, and Timberbottom Farm near Bolton (Lancashire), Brougham Hall and Calgarth Hall (Westmorland), and Threlkeld Place (Cumbria); some were explained as relics of Catholic martyrs, but they too took revenge if disturbed. At Warbleton Priory (Sussex), there were two, allegedly a former owner and his murderer, supposed to cause ghastly noises and bring ill luck if moved; they were still there in 1947 (Simpson, 1973: 47-8).

The origin tales are very varied. At Bettiscombe Manor, near Lyme Regis (Dorset), the skull is said to be that of a Negro slave enraged at not being sent home to Africa for burial; in fact it is female, fossilized, and possibly prehistoric. At Burton Agnes Hall (Yorkshire, now Humberside), it is the youngest of three sisters in Elizabethan times, who on her deathbed made her sisters swear to keep her head on a table so that she could see the Hall completed. The famous ‘Dicky’ of Tunstead Farm (Derbyshire), already installed in 1790, is said to have been a rightful heir in Elizabethan times, murdered by his cousins (Folk-Lore 41 (1930), 98-9); he was buried in the garden in 1985 (Billingsley, 1998: 165-6).

Skulls were used in traditional cures, usually for epilepsy but sometimes also for headaches and plague; either water was drunk from them, or fragments were grated into food. Moss scraped from an old skull was said to staunch bleeding; a tooth from one cured toothache (Opie and Tatem, 1989: 359-60). In Devonshire in the 1880s, a woman whose husband had left her tried to buy from a chemist a substance called ‘Oil of Man’, made by distilling the skulls of hanged men, believing that by burning it she would call him back; she was disappointed to learn that ‘that article cannot be had now’ (Transactions of the Devonshire Association 21 (1889), 113-14).

See also BONES.

Bibliography
The full bibliography list is available here.

• The fullest listing of protective skulls is by Andy Roberts and David Clarke, Fortean Studies 3 (1996), 126-58
• the same authors have collected current beliefs and tales about them in their Twilight of the Celtic Gods (1996), 138-46
• see also Westwood, 1985: 13-4, 327-8

Bones of the head and face. The skull is composed of the cranium enclosing and protecting the brain, and the facial bones.

Skull
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The bony framework of the head consisting of two parts, the cranium and the facial section.
The cranium is the domed top, back and sides of the skull that protects the brain. It is made up mostly of a roof of flat membrane bones united by sutures in the young, plus a series of cartilage bones at the base (occipital, sphenoid). Paranasal sinuses variably excavate the membrane bones.
The facial bones are mostly membrane bones and serve to support the dental arcades and the respiratory passages of the head.

• s. bones — the bones of the skull are the basisphenoid, ethmoid, frontal, hyoid, incisive, interparietal, lacrimal, nasal, occipital, nasal conchal, palatine, parietal, presphenoid, pterygoid, sphenoid, temporal, vomer and zygomatic.
• brachycephalic s. — short, broad skull.
• dolicocephalic s. — long, narrow skull.
• mesaticephalic s. — a medium skull in terms of width and length.
• s. symmetry — asymmetry common only in foals in which the lower part of the face is deviated to one side, involving mandibles, maxillae and nasal bones.

For other uses of "Skull", see Skull (disambiguation).

"Cranium" redirects here. For other uses, see Cranium (disambiguation).

A closeup of the front of a human skull.

The skull is a bony structure found in many animals which serves as the general framework for the head. The skull supports the structures of the face and protects the head against injury.

The skull can be subdivided into two parts: the cranium and the mandible. A skull that is missing a mandible is only a cranium; this is the source of a very commonly made error in terminology. Those animals having skulls are called craniates.

Protection of the brain is only one part of the function of a bony skull. For example, a fixed distance between the eyes is essential for stereoscopic vision, and a fixed position for the ears helps the brain to 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.

Human skulls

Main article: Human skull

Human skull (front)

Human skull (side)

In humans, the adult skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, rigid articulations permitting very little movement. Eight bones form the neurocranium (braincase), a protective vault surrounding the brain. Seventeen bones form the skunt, the bones supporting the face. Encased within the temporal bones are the six ear ossicles of the middle ears, though these are not part of the skull. The hyoid bone, supporting the tongue, is usually not considered as part of the skull either, as it does not articulate with any other bones, though it may be considered a part of the skunt.

The skull contains the sinus cavities, which are air-filled cavities lined with respiratory epithelium, which also lines the large airways. The exact functions of the sinuses are unclear; they may contribute to lessening the weight of the skull with a minimal reduction in strength,or they may be important in improving the resonance of the voice. In some animals, such as the elephant, the sinuses are extensive. The elephant skull needs to be very large, to form an attachment for muscles of the neck and trunk, but is also unexpectedly light; the comparatively small brain-case is surrounded by large sinuses which reduce the weight. The meninges are the three layers, or membranes, which surround the structures of the nervous system. They are known as the dura mater, the arachnoid mater and the pia mater. Other than being classified together, they have little in common with each other.

In humans, the anatomical position for the skull is the Frankfurt plane, where the lower margins of the orbits and the upper borders of the ear canals are all in a horizontal plane. This is the position where the subject is standing and looking directly forward. For comparison, the skulls of other species, notably primates and hominids, may sometimes be studied in the Frankfurt plane. However, this does not always equate to a natural posture in life.

Possible types of skull fractures

The protection of the brain and other vascular and respitory structures provided by the skull, can be compromised if the skull is fractured. Various types of fractures are described below.

Mid-facial Skeletal fracture

The mid facial skeleton is made up of a considerable number of bones which are rarely, if ever, fractured in isolation

The structure is such that it is able to withstand considerable force from below, but the bones are easily fractured by relatively trivial forces applied from other directions

Analogous to a ‘matchbox’ sitting below and in front of a hard shell containing the brain and differs quite markedly from the rigid projection of the mandible below

Le Fort I Fractures

Low-level / Guerin type fractures

Horizontal fracture of the maxilla immediately above the teeth and palate

Piriform fossa across maxilla to pterygoid fissure

May occur as a single entity or in association with le fort II and III fractures

Sometimes present in association with a downwardly displaced fracture of the zygomatic complex

Le Fort II Fractures

Pyramidal or suprazygomatic fractures

Fracture extends from dorsum of nose, across medial walls of orbit across the maxilla below the zygomatic bone to the pterygomaxillary fissure

Le Fort III Fractures

High level or suprazygomatic fractures

The facial bones, including the zygomas are detached from the anterior cranial base

Fracture line extends from the dorsum of the nose and cribiform plate along the medial and up

the lateral wall of the orbit to the ZF suture

Animal skulls

Temporal Fenestra

This Tyrannosaurus skull shows it was a diapsid

The temporal fenestra are anatomical features of the amniote skull, 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 is 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 the more advanced sauropsids and synapsids did. As time progressed, sauropsids' 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

Humans, despite having lost their fenestrae, are synapsids

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

Evolutionary, they are related like so:

• Amniota
  • Class Synapsida - mammal-like reptiles
    • Order Therapsida
      • Class Mammalia - mammals
  • Class Sauropsida - reptiles
    • Subclass Anapsida
    • (unranked) Eureptilia
      • Subclass Diapsida
        • (unranked) Euryapsida
        • Class Aves - birds

A hippopotamus' skull	A Tyrannosaurus skull	A cat skull, a typical skull of a carnivore	A coypu skull, a typical rodent
A bulldog skull	A gerbil skull	A Homo floresiensis skull

See also

• Bone terminology
• Anatomical terms of location
• Head and neck anatomy
• Phrenology, the pseudoscientific process of determining personality from the shape of the head.
• Skull (symbolism)

References

• White, T.D. 1991. Human osteology. Academic Press, Inc. San Diego, CA.

External links

Wikimedia Commons has media related to:

Skulls

• Animal Skull Collection (Over 300 animal skull images compiled by U.S. high-school teacher)
• Site with pictures of various animal skulls (commercial supplier)
• Skull terminology site by Texas A&M
• Anatomy of cranial cavity.
• Dept of Anth Skull Module
• Skull Anatomy Tutorial.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - kranium, hovedskal, pandeskal
v. tr. - slå en oven i hovedet

idioms:

• out of one's skull    være fra forstanden
• skull and crossbones    dødningehoved med to korslagte knogler under
• skull cap    kalot

Nederlands (Dutch)
schedel

Français (French)
n. - crâne
v. tr. - frapper (qn) à la tête

idioms:

• out of one's skull    débloquer, (crever) d'ennui
• skull and crossbones    tête de mort, pavillon à tête de mort
• skull cap    calotte, kippa

Deutsch (German)
n. - Schädel, Helm
v. - jmdm. auf den Kopf schlagen

idioms:

• out of one's skull    verrückt
• skull and crossbones    Totenkopf (mit gekeuzten Knochen)
• skull cap    (Scheitel)käppchen, Schädeldach

Ελληνική (Greek)
n. - κρανίο, νεκροκεφαλή

idioms:

• out of one's skull    θεόμουρλος, στουπί στο μεθύσι
• skull and crossbones    (μτφ.) πειρατική σημαία
• skull cap    (θρησκ.) καλότα (σκούφος καθολικού κληρικού)

Italiano (Italian)
cranio

idioms:

• out of one's skull    pazzo
• skull and crossbones    teschio e tibie incrociate
• skull cap    papalina

Português (Portuguese)
n. - crânio (m), cérebro (m), caveira (f)

idioms:

• out of one's skull    fora de si
• skull and crossbones    símbolo (m) pirata e de produtos venenosos
• skull cap    barrete (m)

Русский (Russian)
череп, башка

idioms:

• out of one's skull    сильно нервничать, с ума сходить
• skull and crossbones    череп и кости (эмблема смерти)
• skull cap    ермолка, тюбетейка, шапочка, скуфейка

Español (Spanish)
n. - cráneo, sesera, calavera
v. tr. - golpear a alguien en la cabeza

idioms:

• out of one's skull    fuera de los cabales, loco, borracho
• skull and crossbones    calavera y dos huesos cruzados
• skull cap    casquete, gorro casero

Svenska (Swedish)
n. - skalle, kranium, huvudskål

中文（简体） (Chinese (Simplified))
头盖骨, 脑壳, 头脑, 击中...的头颅

idioms:

• out of one's skull    烂醉的, 醉醺醺的
• skull and crossbones    骷髅画, 由骷髅和交叉的大腿骨组成, 象征死亡或危险, 骷髅旗, 旧时的海盗旗
• skull cap    无沿便帽

中文（繁體） (Chinese (Traditional))
n. - 頭蓋骨, 腦殼, 頭腦
v. tr. - 擊中...的頭顱

idioms:

• out of one's skull    爛醉的, 醉醺醺的
• skull and crossbones    骷髏畫, 由骷髏和交叉的大腿骨組成, 象徵死亡或危險, 骷髏旗, 舊時的海盜旗
• skull cap    無沿便帽

한국어 (Korean)
n. - 두개골, 용광로 내벽에 둘러붙은 쇠 찌꺼기, 인텔리
v. tr. - ~의 머리를 때리다

日本語 (Japanese)
n. - 頭蓋, 頭, 頭蓋骨, 頭脳

idioms:

• out of one's skull    正気でない
• skull and crossbones    どくろ
• skull cap    ぴったりした縁なし帽子

العربيه (Arabic)
‏(الاسم) عقل, جمجمه‏

עברית (Hebrew)
n. - ‮גולגולת, ראש, מוח‬
v. tr. - ‮היכה (מישהו) בראשו‬

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