Skull
A skull is a bony structure which serves as the general framework for a head. The skull attempts to protect the brain, acting as a form of natural helmet.
Humans
In humans, the skull is the uppermost portion of the human skeleton. It is made up of a number of bony parts - 7 in the skull proper (neurocranium) and 14 in the facial area (splanchnocranium). There are five main skull sections - one occipital, two frontal, two parietal. The sections are fused together in adults along sutures - metopic, coronal, sagittal and lambdoid. At birth these sutures are fibrous and moveable, necessary for birth and later growth. At the points where sutures meet are fontanelles, the main ones are the anterior and posterior. The posterior fontanelle usually closes by eight weeks but the anterior fontanelle can remain up to eighteen months. The anterior fontanelle is located at the junction of the frontal and parietal bones, it is a 'soft spot' on a baby's forehead. Careful observation will show that you can count a baby's heartrate by observing his or her pulse pulsing softly through the anterior fontanelle.
If the brain is bruised or injured it can be extremely serious. Normally the skull protects the brain from damage through its hard unyieldingness, but in some cases of head injury, there can be raised intracranial pressure through mechanisms such as a subdural haematoma. In these cases the raised intracranial pressure can cause herniation of the brain out of the foramen magnum ('coning') because there is no space for the brain to expand to - this can result in significant brain damage or death unless an urgent operation is performed to relieve the pressure. This is why patients with concussion must be watched extremely carefully.
In earlier times, a skull operation called trepanation was often performed for semi-mystical reasons and not only as an attempted life-saving technique.
The skull also contains the sinus cavities. The meninges are the membranes that separate the brain from the skull.
Bones of the human skull
Cranial bones:
Facial bones:
Foramina of skull base
A list of the holes (foramina) in the base of the skull and what goes through each of them.
Arranged from anterior to posterior:
Referenced By
Icon | Icon (religion) | Sebadoh
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