Which of the following statements is true about an optimal tangential knee projection (Merchant method)?
A) A patellar subluxation is demonstrated as long as the patellae are positioned directly above the intercondylar sulcus.
B) The lateral femoral condyle demonstrates more height than the medial femoral condyle.
C) To demonstrate a patellar subluxation, the quadriceps femoris must be tightly contracted.
D) The central ray and axial view angulation, when added, should equal 100 degrees.

Question

Quizplus · Accepted Answer

In an optimal tangential knee projection using the Merchant method, the lateral femoral condyle should demonstrate more height than the medial femoral condyle. This is because the angle of the x-ray tube is aimed laterally towards the lateral femoral condyle at a 30-degree angle, which results in foreshortening of the medial femoral condyle. A patellar subluxation is not demonstrated by the position of the patellae alone and the quadriceps femoris does not need to be tightly contracted. The sum of the central ray and axial view angulation can vary but should be within the range of 45-60 degrees.

Which of the Following Statements Is True About an Optimal