Basion-axial interval
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- updated 15 Jul 2022:
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The basion-axial interval (BAI) is the horizontal distance between the basion and the posterior cortex of the axis, used in the diagnosis of atlanto-occipital dissociation injuries.
It is the distance (in mm) between the basion and the superior extension of the posterior cortical margin of the body of the axis in the median (midsagittal) plane.
Normal values are <12 mm on plain radiographs and were not. This value was found to be reliable ofunreliable on CT 1 they rangethe basion-axial interval ranged from -8.7 mm to +2626 mm in normal subjects1.
See also
-<p>The <strong>basion-axial interval (BAI) </strong>is the horizontal distance between the <a href="/articles/basion">basion</a> and the posterior cortex of the <a href="/articles/axis-c2">axis</a>, used in the diagnosis of <a href="/articles/atlanto-occipital-dissociation-injuries">atlanto-occipital dissociation injuries</a>.</p><p>It is the distance (in mm) between the basion and the superior extension of the posterior cortical margin of the body of the axis in the median (midsagittal) plane.</p><p>Normal values are <12 mm on plain radiographs and were not found to be reliable of on CT <sup>1 </sup>where they range from -8.7 mm to +26 mm in normal subjects.</p><h4>See also</h4><ul><li><a href="/articles/basion-dens-interval">basion-dens interval</a></li></ul>- +<p>The <strong>basion-axial interval (BAI) </strong>is the horizontal distance between the <a href="/articles/basion">basion</a> and the posterior cortex of the <a href="/articles/axis-c2">axis</a>, used in the diagnosis of <a href="/articles/atlanto-occipital-dissociation-injuries">atlanto-occipital dissociation injuries</a>.</p><p>It is the distance (in mm) between the basion and the superior extension of the posterior cortical margin of the body of the axis in the median (midsagittal) plane.</p><p>Normal values are <12 mm on plain radiographs. This value was found to be unreliable on CT where the basion-axial interval ranged from -8.7 mm to 26 mm in normal subjects <sup>1</sup>.</p><h4>See also</h4><ul><li><a href="/articles/basion-dens-interval">basion-dens interval</a></li></ul>
References changed:
- 1. Rojas C, Bertozzi J, Martinez C, Whitlow J. Reassessment of the Craniocervical Junction: Normal Values on CT. AJNR Am J Neuroradiol. 2007;28(9):1819-23. <a href="https://doi.org/10.3174/ajnr.a0660">doi:10.3174/ajnr.a0660</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/17893223">Pubmed</a>
- 1. Rojas CA, Bertozzi JC, Martinez CR et-al. Reassessment of the craniocervical junction: normal values on CT. AJNR Am J Neuroradiol. 2007;28 (9): 1819-23. AJNR Am J Neuroradiol (full text) - doi:10.3174/ajnr.A0660 - Pubmed citation
Images Changes:
Image 1 Annotated image (Basion-axial interval) ( update )
Caption
was added:
Figure 1: base of skull lines (annotated images)
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