Atlanto - axial joint - wikipedia Atlanto - axial joint Atlantoaxial joint Anterior atlantooccipital membrane and atlantoaxial ligament Posterior atlantooccipital membrane and atlantoaxial ligament Details Identifiers Latin Articulatio atlantoaxialis mediana, articulatio atlantoaxialis lateralis MeSH D001268 TA A03. 2.04. 001 A03. 2.05. 001 FMA 25524 Anatomical terminology ( edit on Wikidata ) The atlantoaxial joint is a joint in the upper part of the neck between the first and second cervical vertebrae ; the atlas and axis. It is a pivot joint. The atlantoaxial joint is of a complicated nature. It consists of no fewer than four distinct joints. There is a pivot articulation between the odontoid process of the axis and the ring formed by the anterior arch and the transverse ligament of the atlas. Contents 1 Lateral and median joints 2 Ligaments 3 Capsule 4 Abnormal widening 5 References 6 Bibliography 7 External links Lateral and median joints There are three atlantoaxial joints : one median and two lateral : The median atlantoaxial joint is sometimes considered a triple joint : one between the posterior surface of the anterior arch of atlas and the front of the odontoid process one between the anterior surface of the ligament and the back of the odontoid process The lateral atlantoaxial joint involves the lateral mass of atlas and axis. Between the articular processes of the two bones there is on either side an arthrodial or gliding joint. Ligaments The ligaments connecting these bones are : Articular capsules Anterior atlantoaxial ligament Posterior atlantoaxial ligament Transverse ligament of the atlas The atlantoaxial joint in common terminology is actually a composition of three : two lateral and one median atlantoaxial joints. Because of its proximity to the brain stem and importance in stabilization, fracture or injury at this level can be catastrophic. Common trauma and pathologies include ( but are not limited to ) : The Dens : significant depression on the skull can push the dens into the brainstem, causing death. The dens itself is vulnerable to fracture due to trauma or ossification. Transverse ligament : Should the transverse ligament of the atlas fail due to trauma or disease, the dens is no longer anchored and can travel up the cervical spine, causing paralysis. If it reaches the medulla death can result. Alar ligaments : stress or trauma can stretch the weaker alar ligaments, causing an increase in range of motion of approximately 30 %. Posterior atlanto - occipital membrane : genetic traits can sometimes result in ossification, turning the groove into a foramen. Capsule The atlantoaxial articular capsules are thick and loose, and connect the margins of the lateral masses of the atlas with those of the posterior articular surfaces of the axis. Each is strengthened at its posterior and medial part by an accessory ligament, which is attached below to the body of the axis near the base of the odontoid process, and above to the lateral mass of the atlas near the transverse ligament. Abnormal widening Normal atlanto - dental joint on projectional radiography. A widening of the atlanto - axial joint, as measured between the posterior surface of the anterior arch of atlas and the front of the odontoid process, indicates an injury to the transverse atlantal ligament. Normally, this atlanto - dental distance is less than 2 mm, sometimes a maximum of 3 mm is accepted in men and 2.5 mm in women. References Jump up ^ Federative Committee on Anatomical Terminology ( 1998 ). Terminologia anatomica : international anatomical terminology. Thieme. pp. 27 --. ISBN 978 - 3 - 13 - 114361 - 7. Retrieved 17 June 2010. Jump up ^ Carmine D. Clemente ( 2010 ). Clemente 's Anatomy Dissector. Lippincott Williams & Wilkins. pp. 361 --. ISBN 978 - 1 - 60831 - 384 - 6. Retrieved 17 June 2010. Jump up ^ `` Lateral atlantoaxial joint ''. Medcyclopaedia. GE. ^ Jump up to : Rojas, C.A. ; Bertozzi, J.C. ; Martinez, C.R. ; Whitlow, J. ( 2007 ). `` Reassessment of the Craniocervical Junction : Normal Values on CT ''. American Journal of Neuroradiology. 28 ( 9 ) : 1819 -- 1823. doi : 10.3174 / ajnr. A0660. ISSN 0195 - 6108. Bibliography Dalley, Arthur F ; Moore, Keith L. Clinically Oriented Anatomy Fourth Edition. Baltimore. Lippincott Williams & Wilkins, 1992. Saladin, Kenneth S. Anatomy &Physiology : the Unity of Form and Function. New York. McGraw Hill, 2007. External links `` Anatomy diagram : 25420.000 - 1 ''. Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on 2014 - 01 - 01. Joints and ligaments of the head and neck Temporomandibular Capsule Articular disk Lateral Temporomandibular ligament Medial Sphenomandibular ligament Stylomandibular ligament Atlanto - occipital capsule membranes ( anterior atlantoöccipital membrane posterior atlantoöccipital membrane ) Retrieved from `` https://en.wikipedia.org/w/index.php?title=Atlanto-axial_joint&oldid=835114984 '' Categories : Joints Joints of the head and neck Bones of the vertebral column Hidden categories : Pages with unresolved properties All articles with dead external links Articles with dead external links from September 2016 All articles with unsourced statements Articles with unsourced statements from June 2010 Talk Contents About Wikipedia فارسی Français Italiano Polski Русский Suomi Svenska 中文 Edit links This page was last edited on 6 April 2018, at 17 : 06 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. 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Question: the atlantoaxial joint is an example of what type of joint
Answer: a pivot joint