ABO Cephalometric Analysis and Radiographic Interpretation

Question 1

What is the normal value for the SNA angle in cephalometric analysis?

Accepted Answer

82°

Answer

The normal SNA angle is 82° (±2°), representing the anteroposterior position of the maxilla relative to the cranial base.

Question 2

Which cephalometric landmark is defined as the most posterior-superior point of the pituitary fossa?

Accepted Answer

Sella

Answer

Sella (S) is located at the center of the sella turcica and serves as the origin of the sella-nasion reference line.

Question 3

The Frankfort Horizontal plane is constructed between which two cephalometric landmarks?

Accepted Answer

Porion to Orbitale

Answer

The Frankfort Horizontal is drawn from Porion (superior border of external auditory meatus) to Orbitale (lowest point of the orbital rim).

Question 4

Which cephalometric analysis first introduced the concept of measuring facial convexity angle to evaluate the skeletal profile?

Accepted Answer

Downs analysis

Answer

Downs analysis (1948) introduced the facial convexity angle, measuring the convexity of the face from Nasion-A point-Pogonion.

Question 5

In standard cephalometric analysis, the mandibular plane is most commonly constructed from which landmarks?

Accepted Answer

Gonion to Menton

Answer

The mandibular plane is typically drawn from Gonion (Go) to Menton (Me), representing the inferior border of the mandible.

American Board of Orthodontics (ABO) Practice Test