In Steiner's analysis, SNA demonstrates:
Relating the Maxilla to the Skull: The angle SNA is formed by joining the lines S-N and N-A . The mean reading for this angle is 82°.
Steiners analysis demonstrates the position of maxilla and mandible in relation to the cranial base. 
If the angular reading is more than 82°, it would indicate a relative forward positioning or protrusion of the maxilla. Conversely, should the reading be less than 82°, it would indicate a relative backward or recessive location of the maxilla.
Position of mandible in relation to cranial base
Position of maxilla in relation to cranial base
Maxillo-mandibular relationship
None of the above