Pathologies associated with air or free air are classified as: ...

[newyorker26]

Pathologies associated with air or free air are classified as:
 
 compensating
  terminal
  additive
  destructive

Question 2

Where is the central ray directed for AP obliques of the SI joints?
 
 at the level of the ASIS
  1 inch medial from the upside ASIS
  1 inch superior and 1 inch medial from the iliac crest
  1 inch medial from the downside ASIS

[jordangronback]

Answer to Question 1

destructive

Rationale: Destructive pathologies allow photons to easily penetrate the tissue and result in increased density. Examples of destructive pathologies would be: pneumoperitoneum, osteoporosis, ileus, pneumothorax.

Answer to Question 2

1 inch medial from the upside ASIS

Rationale: AP oblique projections will require the patient to be placed into the RPO and LPO position. The SI joint furthest from the image receptor will open up on posterior oblique positions; therefore the CR should be directed 1 inch medial to the upside ASIS.