A radiograph of a lateral cranium reveals that the mentum was cut off from the bottom of the radiograph. A 24 ´ 30-cm (10 ´ 12-inch) IR was used, and it was placed crosswise. What must be altered if a repeat exposure is performed?1. Increase the extension of the skull2. Increase the flexion of the skull3. Increase the CR angulation4. None of the above positioning was correct

The correct answer is

4. None of the above; centering and image receptor placement were correct.

Explanation:

The best positioning line is perpendicular to the IR for a PA projection of the skull is 10 x 12 inches (24 x 30 cm) lengthwise.

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.

the answer is c because it is most logical.