Radiology · patient case question
What instruction was missed in producing this panoramic radiograph?
Patient case: Infection control and a poor panoramic film
Patient: Practice-based scenarios
Chief Complaint: Not applicable.
Background: A surgical extraction is scheduled and the patient's adult daughter asks to remain in the operatory to support her. A separate patient on the list has ACTIVE pulmonary tuberculosis and needs urgent care. Environmental surfaces are being reviewed after an inspection.
Findings: A panoramic radiograph taken earlier in the day shows a broad dark radiolucent band running across the apices of all the maxillary teeth, obscuring the region of interest. The patient was positioned correctly in the horizontal and vertical planes and the spine is straight.
Show answer and explanation
Correct answer: B. Place the tongue against the hard palate and keep the lips closed throughout the exposure
- A. Failing to bite into the notch produces HORIZONTAL positioning errors: too far forward gives narrowed, blurred anterior teeth with the cervical spine superimposed; too far back gives widened, magnified anterior teeth. The stem states horizontal position was correct.
- B. CORRECT. This is the TONGUE DROP artifact, among the commonest of all panoramic technique errors. If the tongue is not held against the roof of the mouth for the ENTIRE exposure, an air space persists between the dorsum and the palate, and that air produces a dark RADIOLUCENT BAND superimposed across the maxillary apices — obscuring precisely the region being examined. The lips must also remain closed, or a second radiolucency appears over the anterior teeth. The effect is accentuated in EDENTULOUS patients and in patients positioned too far forward. Despite being so frequent, it is rarely on its own a reason to retake the film.
- C. Slumping of the spine projects the cervical vertebrae as a radiopaque pyramid over the anterior mandible — a radiOPACITY, the opposite of what is described here, and excluded by the stem.
- D. Incorrect occlusal plane angulation is a VERTICAL error: chin too high flattens or reverses the smile line and superimposes the hard palate over the maxillary roots; chin too low exaggerates the curve and gives the classic ‘V’ shape. The stem excludes this.
Note: The soft-tissue tongue-drop artifact is new. The two soft tissue projection errors to know are tongue drop and failure to close the lips; the ghost image, by contrast, is a genuine second image of a dense object, appearing on the OPPOSITE side, HIGHER and more magnified and blurred than the real one.