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Banaccconstructedskullxr

Published: August 9, 2026Updated: August 16, 2026

A radiographic measurement that evaluates facial bone structure and growth patterns by analyzing the angle of the facial axis on a skull X-ray.

Quick summary

{"Measures facial bone alignment using skull X-ray imaging","Helps assess jaw growth and facial symmetry","Used in orthodontics and oral surgery planning","Involves analyzing the constructed gnathion angle","Non-invasive imaging test with minimal radiation exposure"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
60627-7
Short code
FAXIS
Synonyms
BaNa-CC (constructed) Skull XR
Category
chemistry
Sample
serum
Container
Not applicable - imaging study, no specimen container required
Units
N/A
Ref low
85
Ref high
95
Fasting
false
Population
adult
Sex
all
Age range
7–99 years
Method
xr-measured
CPT
70350
SNOMED
719029002
Specimen volume
5 mL
Stability
Not applicable - radiographic images should be stored per institutional imaging retention policies (typically 5-10 years minimum)
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

What is this test?

The Facial Axis test is a radiographic measurement that evaluates the growth and alignment of facial bones by analyzing a skull X-ray. Specifically, it measures the 'facial axis' angle using the constructed gnathion (the lowest point of the chin on the X-ray). This measurement helps healthcare providers assess facial skeletal structure, jaw positioning, and growth patterns. The test is commonly used in orthodontic treatment planning and oral-maxillofacial surgery to determine the relationship between the upper and lower jaws.

How is the test performed?

During this test, you will undergo a skull X-ray (cephalometric radiograph). The technologist will position your head in a standardized manner to ensure accurate measurements. The X-ray captures your facial and skull bones, which are then analyzed by your dentist, orthodontist, or oral surgeon. Using specialized software or manual tracing, they measure the angle formed by the facial axis line passing through key anatomical points. This entire process is painless and typically takes just a few minutes for the imaging portion.

What to expect during the procedure

You will be asked to stand or sit in front of the X-ray machine with your head positioned against a stabilizing device. You may need to hold still and possibly hold your breath briefly while the X-ray is taken. The procedure is quick, non-invasive, and does not require any blood draw or injections. The radiation exposure from a skull X-ray is minimal and considered safe for diagnostic purposes.

Reference range

Facial axis measured from constructed gnathion reference point on lateral skull radiograph. Normative value typically ranges from 85° to 95° in balanced facial profiles. Values outside this range may indicate skeletal discrepancies.N/A

Specimen: serum

Remove all metallic objects including earrings, hair clips, dentures, and removable orthodontic appliances. Patient should be in natural head position with teeth in centric occlusion during radiograph exposure.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Does this test require any special preparation?
No special preparation is needed. You may be asked to remove metal objects (jewelry, glasses, hair clips) that could interfere with the X-ray image. Inform your healthcare provider if you are pregnant or might be pregnant.
Is the radiation from a skull X-ray dangerous?
The radiation exposure from a skull X-ray is very low and considered safe for diagnostic purposes. The benefits of obtaining crucial diagnostic information typically outweigh the minimal risks associated with the small amount of radiation.
How long does it take to get results?
The X-ray images are typically available immediately after the procedure. Your healthcare provider will analyze the facial axis measurement and discuss the results with you during a follow-up appointment, usually within a few days to a week.
Who performs this test?
A dental or medical radiologic technologist performs the X-ray, while a dentist, orthodontist, or oral-maxillofacial surgeon interprets the measurements and explains the results to you.
  1. 1
    American Dental Association - Dental Radiographic ExaminationsSource
  2. 2
    Mayo Clinic - X-raySource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy