Skull

As the skull ( cranium Latin from Greek κρανίον kranion ) are referred to the bones of the head of vertebrates. The following section of the skeleton is accordingly called " postcranial " ( postcranial skeletons ). Intracranial means " located in the skull ".

General

The skull is a general feature of all vertebrates. Analogous developments are there in arthropods, such as insects and crustaceans, in which the Oberschlundganglion is protected by the exoskeleton. Even closer is the parallel development in cephalopods ( squid ). These mollusks have a cartilaginous capsule, which protects the brain, and the brain is functionally comparable skull. In the evolution of vertebrates, the earliest forms of the skull developed in the ancestors of bony fish (see → Fish skull).

The bones of the skull

The skull of man consists of 22-30 interconnected via sutures bone. The various types of information based on the fact that on the one hand the skull probably forms two bones systems, but shows after the end of growth mostly as a single bone, on the other hand, the hyoid bone and the ossicles are counted only occasionally to the skull bone. Anatomically, therefore, a distinction the

The bones of the cranium

Morphologically the cranium into the cranial vault ( calvaria, calvarium ) and the skull base is divided. The cranium is formed by

Some authors throughout the frontal bone is associated with the cranium.

The cranium is connected through the head joints of the cervical spine.

The bones of the facial skeleton

For craniofacial include, inter alia, those bones that form the eyes and nasal cavities and the oral cavity. Specifically, these are:

Comparison: human and other apes

The question the skull differences between humans and apes are mainly due to the fact of the complete erection of the human body and the upright posture of humans. The head poised now on the spine, so that the neck muscles in humans is not as strong and, accordingly, the skull bones are thin-walled. On the other hand, the face of the human skull is smaller, the jawline is regressed and the cranium continues to offer the larger brain space.

Growth of the human skull

In newborn humans, the parts of the skull are not yet completely ossified and fused. Between the skull plates are bone gaps that fontanelles. During the first years of life, the fontanelles and cranial skull close completely ossified. At the cranial sutures ( sutures ) of an adult nor the individual plate bones of the skull are also apparent in the head to identify the seam between the two brow bone proportions is usually followed by 2 years of age. Join one or more cranial sutures prematurely, then one speaks of Craniosynostose ( craniosynostosis ). In neonates, the ratio of brain to skull face skull still 8:1, the five year old child 4:1, 2:1 in the adult.

Schädelkinese

Under Schädelkinese or kinetics refers to the mobility of some cranial regions relative to each other. Such flexibility is found in all extant birds ( at the Urkiefervögeln, such as the African ostrich, however, only limited) and many ( recent and fossil ) reptiles, as with all snakes and most lizards (function here is very unclear). So in birds and some reptiles exists an additional joint in the skull roof in front of the eye sockets, which allows them, by lateral rotation of the Quadratums the roof of the mouth against the skull in front and move back. The thus achieved enhanced uplift of the upper jaw enlarged the mouth and possibly the bite force. The Schädelkinese leads the birds to a great variety of forms and is responsible not only for their skill in the manipulation of food, but also lessens the impact of some birds pecking at and also plays a role in nest building and preening. It is also of systematic importance, because due to the relationships of the palate bone, which are involved in the moving process, four or more taxa of extant birds are distinguished. - Furthermore, these kinetics some amphibians and most fish comes to the coelacanth even in the cranium. - In mammals, however, the different regions of the skull are (except for the lower jaw ) are mutually rigid - her skull is akinetic. ( The slight movements of the bones in the sutures, which are for the " craniosacral therapy " of importance, are not covered by Kinesis. )

Symbolism

On graves and grave stones of the skull suggests the transience of life. He's iconographic feature of many holy penitents and hermits, with pictures of the church father Jerome, he is part of the standard program. With the devastating occurrence of plague occur since the 15th century, the dance of death images that are provided with whole skeletons, individual bones and skulls. The skull is often a component of baroque vanitas still life. Again, it is meditation object, which is to remind the viewer of the transience of life. Frequently found on crucifixion scenes at Jesus' feet a skull. Here is an allusion to a medieval legend that the cross of Christ has been built on the grave of Adam.

Wizards, Witches and occultists are often associated with skulls. He is, as well as in art, illustrate the mortality of people in their environment and their own mortality.

In the gothic culture skull be used as a piece of jewelry.