The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
The cranium, a portion of the skull commonly referred to as the braincase, describes the hard, skeletal structure of the head and face. The bones of the cranium possess distinctive features that allow easy identification of their position and orientation in the body. The human adult mandible, or lower jaw, is not generally considered by anatomists to be a part of the cranium.
The adult human cranium consists of 22 bones: 14 facial bones and 8 cranial bones. The cranial bones are the parietals, located at the top and sides of the skull, two temporal bones above the ears, the ethmoid around the nose, the sphenoid at the base of the skull, the frontal over the forehead, and the occipital. The occipital bone at the back of the skull forms a complex joint with the first vertebra of the neck (atlas) that permits nodding and rotation of the head.
At birth, the cranial bones are still forming and skull joints are soft and flexible. This allows the baby's head to compress and easily pass through the birth canal. The so-called "soft spots" on an infant's skull are termed as fontanels, areas where the bones of the cranium do not meet. Cranial bones fuse together in dovetailed, immovable joints called sutures, which make the skull rigid. By age two, the bones become mostly fused, but full fusion often does not occur until late in puberty.
Rare conditions such as Osteitis Deformans and Acromegaly can cause the bones of the skull to grow larger than normal. Falls, blows to the head and others accidents can cause the skull bones to crack and break. Skull fractures can be serious due to the proximity to neural tissue in the brain or the subsequent swelling of membranes (e.g., meningeal membranes) covering the central nervous system tissue.