Fielding-Hawkins (Atlantoaxial Rotatory Subluxation)
The Fielding-Hawkins classification of atlantoaxial rotatory subluxation / fixation, by the direction and degree of atlas displacement on the axis, types I/II/III/IV.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Fielding-Hawkins type
- II - anterior 3-5 mm (transverse ligament deficient)
Result: Fielding-Hawkins type II: rotatory fixation with anterior displacement of 3 to 5 mm.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Type I
- No anterior displacement (ADI <= 3 mm); odontoid pivot.
- Type II
- Anterior displacement 3 to 5 mm; transverse ligament deficient.
- Type III
- Anterior displacement > 5 mm; transverse and alar ligaments deficient.
- Type IV
- Posterior displacement of the atlas.
What you enter
- Fielding-Hawkins type
How this is calculated
Fielding JW, Hawkins RJ. Atlanto-axial rotatory fixation. (Fixed rotatory subluxation of the atlanto-axial joint). J Bone Joint Surg Am. 1977;59(1):37-44. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.