Description
Return angle at a supplied three-landmark vertex.
Anatomical diagrams and idealized models require explicit coordinate origins, axes, dimensions and indexing conventions. Translations, vector projections and simple shape formulas describe supplied geometry rather than identifying actual anatomy or determining a medical finding. A scaled drawing or ideal branching tree needs separate anatomical verification.
Return angle at a supplied three-landmark vertex.
When to use this tool
Use Anatomical Angle Three Landmark Term when checking the stated diagram, coordinate, vector or ideal-shape convention.
How to use the tool and how it works
- Enter first, vertex, last. Follow any array-alignment requirements below. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read angleRadians. Use the output convention below.
Return angle at a supplied three-landmark vertex. Require length-three points with nonzero vertex arms; normalize both arms, clamp their dot product to [-1,1] and return acos in radians.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| first | First | Required. Array of finite number; maximum items 256. |
| vertex | Vertex | Required. Array of finite number; maximum items 256. |
| last | Last | Required. Array of finite number; maximum items 256. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| angleRadians | Angle in radians on the specified axis/sign convention. | Required. Finite number. |
{
"input": {
"first": [
1,
0,
0
],
"vertex": [
0,
0,
0
],
"last": [
0,
1,
0
]
},
"output": {
"angleRadians": 1.5707963267948966
}
}Limitations and assumptions
- Clamping handles floating-point range drift; actual landmark identity, measurement uncertainty and clinical meaning are not assessed.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use verified anatomical measurements and an appropriate complete spatial model; consult qualified health professionals for actual medical interpretation.
References
Similar or alternative tools
- Anatomical Axis Handedness Triple Sign
Return scalar triple product and handedness label.
- Anatomical Axis Orthogonality Residual
Return normalized anatomical-axis dot product and orthogonality residual.