FACTOID # 94: In pure number terms, more crimes are committed in America than in any other nation. The same goes for burglaries, car thefts, rapes and assaults.
 
 Home   Encyclopedia   Statistics   Countries A-Z   Flags   Maps   Education   Forum   FAQ   About 
 
 
 
WHAT'S NEW
RECENT ARTICLES
More Recent Articles »
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Dens (anatomy)
Bone: Dens (anatomy)
Second cervical vertebra, or epistropheus, from above. (Dens labeled at center top.)
Second cervical vertebra, epistropheus, or axis, from the side. (Odontoid process labeled at center top.)
Gray's subject #21 99
Dorlands/Elsevier d_08/12285795

The dens or odontoid process or odontoid peg of the axis exhibits a slight constriction or neck, where it joins the body. Image File history File links Gray87. ... A diagram of a thoracic vertebra. ... In anatomy, the second cervical vertebra (C2) of the spine is named the axis (from Latin axis, axle) or epistropheus. ... Image File history File links Gray88. ... Elseviers logo. ... In anatomy, the second cervical vertebra (C2) of the spine is named the axis or epistropheus. ...


On its anterior surface is an oval or nearly circular facet for articulation with that on the anterior arch of the atlas. The anterior arch of the atlas forms about one-fifth of the ring of the atlas: its anterior surface is convex, and presents at its center the anterior tubercle for the attachment of the Longus colli muscles; posteriorly it is concave, and marked by a smooth, oval or circular facet...


On the back of the neck, and frequently extending on to its lateral surfaces, is a shallow groove for the transverse atlantal ligament which retains the process in position. The transverse ligament of the atlas is a thick, strong band, which arches across the ring of the atlas, and retains the odontoid process in contact with the anterior arch. ...


The apex is pointed, and gives attachment to the apical odontoid ligament; below the apex the process is somewhat enlarged, and presents on either side a rough impression for the attachment of the alar ligament; these ligaments connect the process to the occipital bone. In the triangular interval between the alar ligaments is another fibrous cord, the ligament of apex dentis (or apical odontoid ligament), which extends from the tip of the odontoid process to the anterior margin of the foramen magnum, being intimately blended with the deep portion of the anterior atlantoöccipital... The alar ligaments connect the sides of the dens (on the axis, or the second cervical vertebra) to tubercles on the medial side of the occipital condyle. ... The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself. ...


The internal structure of the odontoid process is more compact than that of the body.


The odontoid peg is the ascension of the atlas fused to the ascension of the axis. The peg has an articular facet at its front and forms part of a joint with the anterior arch of the atlas. It is a non-weight-bearing joint. The alar ligaments, together with the apical ligaments, are attached from the sloping upper edge of the odontoid peg to the margins of the foramen magnum. The inner ligaments limit rotation of the head and are very strong. The weak apical ligament lies in front of the upper longitudinal bone of the cruciform ligament, and joins the apex of the deltoid peg to the anterior margin of the foramen magnum. It is the fibrous remnant of the notochord.



Dens is also another word for 'teeth', hence the name 'DENTIST'.


Fracture Types


A type I Fracture extends through the tip of the dens. A type II fracture is through the body and is the most common type. A type III fracture extends through the vertebral body of the vertebra.[1]


Additional images

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant. Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... The University of Michigan, Ann Arbor (UM, U of M or U-M) is a coeducational public research university in the U.S. state of Michigan. ... The University of Michigan, Ann Arbor (UM, U of M or U-M) is a coeducational public research university in the U.S. state of Michigan. ... The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind in the Borough of Brooklyn in New York City. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body (or Grays Anatomy as it has more commonly become known) is an anatomy textbook widely regarded as a classic work on human anatomy. ...



 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Lesson Plans | Student Area | Student FAQ | Reviews | Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m