Atlantodental interval

Last revised by Ryan Thibodeau on 11 Oct 2023

Citation, DOI, disclosures and article data

Citation:

Hacking C, Thibodeau R, Chieng R, et al. Atlantodental interval. Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-40483

DOI:

https://doi.org/10.53347/rID-40483

Permalink:

https://radiopaedia.org/articles/40483

rID:

40483

Article created:

23 Oct 2015, Craig Hacking ◉ ◈

Disclosures:

At the time the article was created Craig Hacking had no recorded disclosures.

View Craig Hacking's current disclosures

Last revised:

11 Oct 2023, Ryan Thibodeau ◉

Disclosures:

At the time the article was last revised Ryan Thibodeau had no financial relationships to ineligible companies to disclose.

View Ryan Thibodeau's current disclosures

Revisions:

12 times, by 10 contributors - see full revision history and disclosures

Systems:

Central Nervous System, Spine, Trauma

Sections:

Approach, Anatomy

Tags:

cases, case2

Synonyms:

Atlantodental interval (ADI)
Atlanto-dental interval (ADI)

The atlantodental interval is used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis.

The lateral atlantodental interval is the horizontal distance between the lateral cortex of the dens and the medial cortex of the lateral masses of the atlas. The normal value is 3.4 mm in either right or left atlantodental interval. However, normal asymmetry between right and left atlantodental interval can vary up to 0.76 mm. Therefore, asymmetry in lateral atlantodental interval is not a sensitive or specific sign of atlanto-occipital dissociation injuries ².

Interpretation

Normal values for anterior atlantodental interval are:

radiographs
- adults
  - males: <3 mm
  - females: <2.5 mm ¹ (although some authors do not specifically differentiate from males)
- children: <5 mm ^4-7
CT
- adults: <2 mm ¹
- children: <2.6 mm ⁵