The midline of the upper arm before and after photography is

In the anteroposterior photography of the upper arm, the inlet point of the center line is perpendicular to the midpoint of the humerus. According to relevant data: aim at the middle point of humerus and shoot into the cassette vertically. The patient lies on his back on the photographic table, slightly lifts the opposite shoulder, so that the upper arm of the examined side is as close as possible to the film box, the upper arm of the examined side is slightly separated from the trunk, and the elbow joint is bent.