Radiography Exam Patient Positioning & Procedures 2 — Questions and Answers
Question 1: Which radiographic projection best demonstrates the interproximal spaces of the posterior teeth?
- Periapical
- Bitewing (Correct answer)
- Panoramic
- Occlusal
Correct answer: Bitewing
Bitewing radiographs are specifically designed to demonstrate the crowns and interproximal (contact) areas of both upper and lower posterior teeth simultaneously.
Question 2: For an AP projection of the pelvis, what is the correct positioning of the lower extremities to demonstrate the femoral necks without foreshortening?
- Externally rotate feet 15–20 degrees
- Internally rotate feet 15–20 degrees (Correct answer)
- Flex knees 90 degrees
- Abduct legs 45 degrees
Correct answer: Internally rotate feet 15–20 degrees
Internal rotation of the feet 15–20 degrees places the femoral necks parallel to the image receptor, eliminating foreshortening.
Question 3: Which projection of the skull best demonstrates the sella turcica in profile?
- AP axial (Towne)
- PA axial (Caldwell)
- Lateral skull (Correct answer)
- Submentovertex (SMV)
Correct answer: Lateral skull
The lateral skull projection places the sella turcica in true lateral profile, making it the best view for evaluating this structure.
Question 4: Which positioning line is used as a reference for the orbitomeatal line (OML)?
- A line from the outer canthus of the eye to the EAM (Correct answer)
- A line from the inner canthus of the eye to the EAM
- A line from the nose tip to the EAM
- A line from the chin to the EAM
Correct answer: A line from the outer canthus of the eye to the EAM
The orbitomeatal line (OML) extends from the outer canthus (lateral corner) of the eye to the external auditory meatus (EAM).
Question 5: For an AP axial projection of the skull (Towne method), the central ray is angled caudally. What is the standard angle when the OML is perpendicular to the IR?
- 15 degrees
- 25 degrees
- 30 degrees (Correct answer)
- 45 degrees
Correct answer: 30 degrees
The Towne method uses a 30-degree caudal angle when the OML is perpendicular to the IR to project the occipital bone and dorsum sellae.
Question 6: Which positioning error causes the appearance of an elongated image on a radiograph?
- Excessive angulation of the central ray
- Insufficient angulation of the central ray (Correct answer)
- Tube tilt perpendicular to the long axis
- SID too long
Correct answer: Insufficient angulation of the central ray
Insufficient central ray angulation (or insufficient part angle) causes the image to appear elongated because the part and film are not properly aligned.
Radiography Exam Patient Positioning & Procedures 2
Which radiographic projection best demonstrates the interproximal spaces of the posterior teeth?