Medical Definition of PA (posteroanterior)

  • Medical Author:
    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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.

Reviewed on 9/7/2018

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