Definition of PA (posteroanterior)

PA (posteroanterior): In anatomy, PA stands for posteroanterior: from back-to-front. For example, a PA X-ray of the chest is taken from back-to-front.

PA in this respect is the opposite of AP which stands for anteroposterior: from front-to-back.


Last Editorial Review: 6/14/2012

Search MedTerms:


Back to MedTerms online medical dictionary A-Z List
Pill Identifier Tool

Need help identifying pills and medications?
Use the pill finder tool on RxList.