Which of the following signifies that the AP elbow was acquired ...

[B]

Which of the following signifies that the AP elbow was acquired with the humerus and forearm on the same plane in full extension?
 
 the space between the radius and capitulum is open
  radial head, neck, and tuberosity are slightly superimposed
  radial head, neck, and tuberosity are free of superimposition
  sign of the 3 concentric rings

Question 2

In reference to the image, which characterizes proper positioning?
 
 the cephalic tube angle is sufficient
  all of these answers apply
  the part is properly flexed
  there is minimal to no rotation of the part

[steff9894]

Answer to Question 1

the space between the radius and capitulum is open

Rationale: A properly positioned AP elbow places the humerus and forearm on the same plane in full extension. This will result in the humeroradial joint being open.

Answer to Question 2

all of these answers apply

Rationale: The image represents a perfect mediolateral projection of the knee. The knee is flexed properly as the patellofemoral joint is open. The condyles are superimposed which is attained with proper cephalic tube angle applied. The condyles are also superimposed indicating that there is no rotation.