skull


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skull

 [skul]
the skeleton of the head, consisting of the cranium and the mandible. The cranium forms the domed top, back, and sides of the skull; several of its bones are large, smooth, gently curved, and connected to each other by dovetailed joints called sutures, which permit no movement and make the mature skull rigid. They protect the brain, with their curved exterior serving to deflect blows; the eyes, ears, and nose are also protected by being recessed into the skull and surrounded by bone.



At birth the skull joints are flexible, so that the infant's head can be compressed as it emerges from the birth canal. The joints remain flexible to allow expansion until the cranial bones are fully formed, around the second year of life. An infant's skull contains soft areas, or fontanels, where the bones of the cranium do not meet.

The skull is supported by the highest vertebra, called the atlas. This joint permits a back-and-forth, nodding motion. The atlas turns on the vertebra below it, the axis, which allows the skull to turn from side to side.
Disorders of the Skull. The skull is rarely affected by disease. Uncommon ones like osteitis deformans and acromegaly cause the bones to increase in size. Like other bones, the skull may be fractured by blows, falls, or other accidents, but skull fracture can be far more dangerous because of its proximity to the brain.
Skull, midsagittal section. From Applegate, 2000.

cra·ni·um

, pl.

cra·ni·a

(krā'nē-ŭm, -ă), [TA]
The bones of the head collectively. The neurocranium is the part of cranium that forms the bony brain case containing the brain, excluding the bones of the face (viscerocranium).
Synonym(s): skull
[Mediev. L. fr. G. kranion]

skull

(skul) the cranium; the bony framework of the head, composed of the cranial and facial bones.

skull

(skŭl)
n.
The bony or cartilaginous framework of the head, made up of the bones of the braincase and face; cranium.

skull

Etymology: ME, skulle, shell
the bony structure of the head, consisting of the cranium and the skeleton of the face. The cranium, which contains and protects the brain, consists of 8 bones; the skeleton of the face is composed of 14 bones.

skull

(skŭl)
The bones of the head collectively. In a more limited sense, the neurocranium, the bony braincase containing the brain, excluding the bones of the face (viscerocranium).
[Mid. Eng. skulle, a bowl]

skull

(skul)
Enlarge picture
BONES OF SKULL: Cranial bones
Enlarge picture
BONES OF SKULL: Facial bones
The bony framework of the head, composed of 8 cranial bones, the 14 bones of the face, and the teeth. It protects the brain and sense organs from injury. Synonym: calvaria; cranium See: illustration; skeleton

fractured skull

See: fracture of skullillustration

skull

The bony skeleton of the head and the protective covering for the brain. The part of the skull that encloses the brain is called the cranium.

skull

the skeleton of the vertebrate head.

cra·ni·um

, pl. crania (krā'nē-ŭm, -ă) [TA]
The bones of the head collectively.
Synonym(s): skull.
[Mediev. L. fr. G. kranion ]

skull

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.

skull 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 skull
short, broad skull.
dolicocephalic skull
long, narrow skull.
mesaticephalic skull
a medium skull in terms of width and length.
skull 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.
References in classic literature ?
At one place, they observed a field decorated with buffalo skulls, arranged in circles, curves, and other mathematical figures, as if for some mystic rite or ceremony.
Why taint noffin but a skull - somebody bin lef him head up de tree, and de crows done gobble ebery bit ob de meat off.
She sought every where for him whose eyes had used to look tenderly into hers out of this poor skull, but she could not find him.
So let us cease this talk of skull crushing and converse upon more pleasant subjects.
As two of the head hunters closed upon him the brave Chinaman clubbed his weapon and went down beneath them beating madly at the brown skulls.
Only short months before this head had been alive, he pondered, quick with wit, attached to a two-legged body that stood erect and that swaggered about, a loincloth and a belted automatic around its middle, more powerful, therefrom, than Bashti, but with less wit, for had not he, Bashti, with an ancient pistol, put darkness inside that skull where wit resided, and removed that skull from the soddenly relaxed framework of flesh and bone on which it had been supported to tread the earth and the deck of the Arangi?
A striking feature of the decorations consisted of several engaged columns set into the walls at no regular intervals, the capitals of each supporting a human skull the cranium of which touched the ceiling, as though the latter was supported by these grim reminders either of departed relatives or of some hideous tribal rite--Bradley could not but wonder which.
A dog, with only three legs, lay behind the stove; a crow sat on a roost above our heads, in company with a matronly old hen; and on the clock shelf were a stuffed monkey and a grinning skull.
Each of us uncovered a great number of these bricks, until we commenced to weary of the monotony of it, when Snider suddenly gave an exclamation of excitement, and, as I turned to look, he held up a human skull for my inspection.
Most physiologists believe that the bones of the skull are homologous with--that is correspond in number and in relative connexion with--the elemental parts of a certain number of vertebrae.
The other day he nearly fractured my skull for singing a pretty, inoffensive love-song, on purpose to amuse him.
Molly pursued her victory, and catching up a skull which lay on the side of the grave, discharged it with such fury, that having hit a taylor on the head, the two skulls sent equally forth a hollow sound at their meeting, and the taylor took presently measure of his length on the ground, where the skulls lay side by side, and it was doubtful which was the more valuable of the two.