Atlanto-axial joint

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Atlanto-axial joint
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Details
System Skeletal
Identifiers
Latin articulatio atlantoaxialis mediana, articulatio atlantoaxialis lateralis
MeSH D001268
FMA 25524
Anatomical terminology

The atlanto-axial joint is a joint in the upper part of the neck between the atlas bone and the axis bone, which are the first and second cervical vertebrae. It is a pivot joint.

Contents

Structure

The atlanto-axial joint is a joint between the atlas bone and the axis bone, which are the first and second cervical vertebrae. It is a pivot joint that provides 40 to 70% of axial rotation of the head. [1]

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.

Lateral and median joints

There are three atlanto-axial joints: one median and two lateral: [2]

Ligaments

The ligaments connecting these bones are:

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.

Clinical significance

Because of its proximity to the brain stem and importance in stabilization, fracture or injury to the atlanto-axial joint can cause serious problems. 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.

Arthritis

Osteoarthritis may occur at the atlanto-axial joint. [5] This involves classic pathophysiology, such as loss of articular cartilage, osteophytes visible with radiography, and bone thickening with a narrow joint space. [5] Conservative management is usually effective, involving analgesics. [5] Surgery may be used in severe cases, and may have good outcomes. [5]

Abnormal widening

Normal atlanto-dental joint on projectional radiography. Normal atlanto-dental joint on X-ray.jpg
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. [6] 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. [6]

Related Research Articles

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<span class="mw-page-title-main">Atlas (anatomy)</span> First cervical vertebra of the spine which supports the skull

In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck.

<span class="mw-page-title-main">Clavicle</span> Long bone that serves as a strut between the scapula and the sternum

The clavicle, collarbone, or keybone is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the right. The clavicle is the only long bone in the body that lies horizontally. Together with the shoulder blade, it makes up the shoulder girdle. It is a palpable bone and, in people who have less fat in this region, the location of the bone is clearly visible. It receives its name from Latin clavicula 'little key' because the bone rotates along its axis like a key when the shoulder is abducted. The clavicle is the most commonly fractured bone. It can easily be fractured by impacts to the shoulder from the force of falling on outstretched arms or by a direct hit.

<span class="mw-page-title-main">Knee</span> Leg joint in primates

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<span class="mw-page-title-main">Axis (anatomy)</span> Second cervical vertebra of the spine

In anatomy, the axis is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The spinal cord passes through the axis.

<span class="mw-page-title-main">Radius (bone)</span> One of the two long bones of the forearm

The radius or radial bone is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer than the radius, but the radius is thicker. The radius is a long bone, prism-shaped and slightly curved longitudinally.

<span class="mw-page-title-main">Cervical vertebrae</span> Vertebrae of the neck

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<span class="mw-page-title-main">Talus bone</span> One of the foot bones that forms the tarsus

The talus, talus bone, astragalus, or ankle bone is one of the group of foot bones known as the tarsus. The tarsus forms the lower part of the ankle joint. It transmits the entire weight of the body from the lower legs to the foot.

<span class="mw-page-title-main">Lateral parts of occipital bone</span> Parts of bone in base of skull

The lateral parts of the occipital bone are situated at the sides of the foramen magnum; on their under surfaces are the condyles for articulation with the superior facets of the atlas.

<span class="mw-page-title-main">Atlanto-occipital joint</span> Articulation between the occipital bone and the cervical atlas

The atlanto-occipital joint is an articulation between the atlas bone and the occipital bone. It consists of a pair of condyloid joints. It is a synovial joint.

<span class="mw-page-title-main">Transverse ligament of atlas</span>

In anatomy, the transverse ligament of the atlas is a broad, tough ligament which arches across the ring of the atlas posterior to the dens to keep the dens in contact with the atlas. It forms the transverse component of the cruciform ligament of atlas.

<span class="mw-page-title-main">Posterior longitudinal ligament</span> Ligament connecting vertebral bodies of all of the vertebrae

The posterior longitudinal ligament is a ligament connecting the posterior surfaces of the vertebral bodies of all of the vertebrae of humans. It weakly prevents hyperflexion of the vertebral column. It also prevents posterior spinal disc herniation, although problems with the ligament can cause it.

<span class="mw-page-title-main">Tectorial membrane of atlanto-axial joint</span> Ligament in the spinal canal in the head joint area

The tectorial membrane of atlanto-axial joint is a tough membrane/broad, strong band representing the superior-ward prolongation of the posterior longitudinal ligament.

<span class="mw-page-title-main">Occipital condyles</span> Undersurface protuberances of the occipital bone in vertebrates

The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra.

<span class="mw-page-title-main">Cruciate ligament of atlas</span> Ligament forming part of theatlanto-axial joint

The cruciate ligament of the atlas is a cross-shaped ligament in the neck forming part of the atlanto-axial joint. It consists of the transverse ligament of atlas, a superior longitudinal band, and an inferior longitudinal band.

<span class="mw-page-title-main">Outline of human anatomy</span> Overview of and topical guide to human anatomy

The following outline is provided as an overview of and topical guide to human anatomy:

<span class="mw-page-title-main">Vertebral column</span> Bony structure found in vertebrates

The vertebral column, also known as the spinal column, spine or backbone, is the core part of the axial skeleton in vertebrate animals. The vertebral column is the defining and eponymous characteristic of the vertebrate endoskeleton, where the notochord found in all chordates has been replaced by a segmented series of mineralized irregular bones called vertebrae, separated by fibrocartilaginous intervertebral discs. The dorsal portion of the vertebral column houses the spinal canal, an elongated cavity formed by alignment of the vertebral neural arches that encloses and protects the spinal cord, with spinal nerves exiting via the intervertebral foramina to innervate each body segments.

<span class="mw-page-title-main">Vertebra</span> Bone in the vertebral column

Each vertebra is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal segment and the particular species.

References

  1. Roche, Clare J.; King, Susan J.; Dangerfield, Peter H.; Carty, Helen M. (2002). "The Atlanto-axial Joint: Physiological Range of Rotation on MRI and CT". Clinical Radiology. 57 (2): 103–108. doi:10.1053/crad.2001.0703.
  2. Federative Committee on Anatomical Terminology (1998). Terminologia anatomica: international anatomical terminology. Thieme. pp. 27–. ISBN   978-3-13-114361-7 . Retrieved 17 June 2010.
  3. Carmine D. Clemente (2010). Clemente's Anatomy Dissector. Lippincott Williams & Wilkins. pp. 361–. ISBN   978-1-60831-384-6 . Retrieved 17 June 2010.
  4. "Lateral atlantoaxial joint". Medcyclopaedia. GE. Archived from the original on 2012-02-05.
  5. 1 2 3 4 Harata, S.; Tohno, S.; Kawagishi, T. (1982-03-01). "Osteoarthritis of the atlanto-axial joint". International Orthopaedics. 5 (4): 277–282. doi:10.1007/BF00271083. ISSN   1432-5195.
  6. 1 2 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. PMC   8134200 . PMID   17893223.

Bibliography