11-13 week scan
Facial angle

FMF Certificate of competence in measurement of the facial angle

The findings of recent studies suggest that fetuses with trisomy 21 have a flat profile because the maxilla (upper jaw) is small and set back. This produces a wide angle in a line drawn over the palate and between the maxilla and the forehead (facial angle). Measurement of the facial angle at 11-13 weeks improves the performance of screening for trisomy 21 by maternal age and fetal NT.

Requirements for Certification in measurement of the facial angle

The requirements for certification are:

1. FMF certification in measurement of nuchal translucency.
2. Attendance of the internet based course on the 11-13 weeks scan.
3. Submission of a logbook of 3 images demonstrating the measurement of the facial angle at 11-13 weeks.

Protocol for measurement of the fetal facial angle

  • The gestational period must be 11 to 13 weeks and six days.
  • The magnification of the image should be such that the fetal head and thorax occupy the whole image.
  • A mid-sagittal view of the face should be obtained. This is defined by the presence of the echogenic tip of the nose and rectangular shape of the palate anteriorly, the translucent diencephalon in the centre and the nuchal membrane posteriorly. Minor deviations from the exact midline plane would cause non-visualization of the tip of the nose and visibility of the zygomatic process of the maxilla.
  • The facial angle should be measured between a line along the upper surface of the palate and a line which traverses the upper corner of the anterior aspect of the maxilla extending to the external surface of the forehead, represented by the frontal bones or an echogenic line under the skin below the metopic suture that remains open.

Clinical application of fetal facial angle measurement

The fetal facial angle decreases with CRL and is wider in fetuses with trisomy 21 than in chromosomaly normal fetuses. It is essential that in adjusting the risk for trisomy 21 using the measurement of the facial angle the software takes into account the fetal CRL.

The FMF software firstly calculates a risk based on maternal age, fetal NT and maternal serum free β-hCG and PAPP-A. If the risk is more than 1 in 50 and and the facial angle is within the normal range the risk does not change. If the risk is 1 in 50 to 1 in 1,000 and the the facial angle is within the normal range the risk is usually reduced. If the facial angle is above the bormal range the risk is always increased.

Quality review and ongoing Certification in measurement of the facial angle

  • Each sonographer must submit 3 images demonstrating the measurement of the facial angle at 11-13 weeks for audit 12 months after obtaining the FMF Certificate of competence in measurement of the facial angle and the FMF software for the calculation of risks. In addition to the FMF audit, all sonographers are encouraged to perform their own internal quality assurance on a regular basis.
  • The audit involves examination of the images for each operator. Sonographers passing their audit will be re-audited and re-licensed on an annual basis thereafter.
  • If the images are not satisfactory the name of the sonographer will be removed from the FMF website list of holders of the Certificate of competence in measurement of the facial angle. A new audit can be carried out subsequently and the sonographer will only be reinstated on the FMF website list and the license renewed once the audit is considered satisfactory.

Submission of logbook

Please login to upload your images:

 

 

Alternatively, send your completed logbook to:

The 11-13 weeks scan: Facial angle
The Fetal Medicine Foundation
137 Harley Street
London, W1G 6BG

Holders of the FMF Certificate in measurement of the facial angle

To view the list of sonographers who have obtained the Certificate of competence in measurement of the facial angle please click here.

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