The AP knee for an asthenic patient requires the central ray to ...

[washai]

The AP knee for an asthenic patient requires the central ray to be directed:
 
 perpendicular to the femorotibial joint
  10 degrees cephalic to the femorotibial joint
  3-5 degrees caudal to the femorotibial joint
  5 degrees cephalic to the femorotibial joint

Question 2

Pathological conditions which are affiliated with tissue atrophy are referred to as:
 
 destructive pathologies
  additive pathologies
  unknown pathologies
  defining pathologies

[yifu223]

Answer to Question 1

3-5 degrees caudal to the femorotibial joint

Rationale: The asthenic patient measures less than 18 cm from the ASIS to the tabletop which results in a very thin patient leg. In order for the CR to pass parallel to the tibial plateau, the tube is angled 3-5 degrees caudal.

Answer to Question 2

destructive pathologies

Rationale: Destructive pathologies are affiliated with tissue necrosis and/or atrophy. Imaging patients with these conditions without alteration of technical factors will result in excessive density on the image.

[washai]

Thanks for the timely response, appreciate it

[flexer1n1]

Great answer, keep it coming