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Anatomy, Physiology & Imaging Orientation for Imaging Informatics

The clinical language that shows up in exam names, image display, and reports - anatomy, physiology, directional terms, body planes, and X-ray projections.

Format: Beginner article · Level: Introductory · Best for: IT and support staff, analysts, new PACS learners, and technologists crossing into informatics

You do not need to be a clinician to work in imaging informatics, but you do need to recognize the clinical language that fills exam names, procedure descriptions, display rules, and reports. This article covers just enough to make that language familiar.

Anatomy vs physiology

Anatomy is structure - where body parts are and how they are arranged: bones, organs, vessels, muscles, joints. It answers "what part is being imaged, and where is the finding?"

Physiology is function - how the body works: the heart pumping, the lungs exchanging air, the kidneys filtering. It helps explain why an exam was ordered and what the team is looking for.

Some exams mainly show structure, some assess function, and many show both.

Why an informatics person should care

A PACS, viewer, worklist, or reporting system looks technical, but the information inside it is clinical. Exam descriptions, body-part values, procedure codes, display layouts, and routing rules all carry clinical meaning. A little anatomy and physiology makes those values readable instead of arbitrary.

Directional terms

Standard terms let everyone describe the body the same way:

Anterior - toward the front (the sternum is anterior).
Posterior - toward the back (the spine is posterior).
Superior - toward the head; Inferior - toward the feet.
Medial - toward the midline (the nose is medial to the ears).
Lateral - away from the midline (the ears are lateral to the nose).
Proximal / Distal - nearer to / farther from the point of attachment (used mostly for limbs; the elbow is proximal to the wrist).

Clothed anatomical figure illustrating superior, inferior, anterior, posterior, medial, lateral, proximal, and distal directions — Directional terms use the body as the reference point. Medial points toward the dashed midline; lateral points away from it. Proximal points toward the limb's attachment, while distal points farther away.

These appear constantly in positioning, image orientation, findings, and reports.

A quick note on image orientation

Medical images are not always displayed the way people expect. Axial CT and MRI images are commonly viewed as if looking up from the patient's feet, so left/right markers matter - correct orientation is essential.

Body planes

Planes describe how the body is sliced or viewed - central to CT and MRI, where images are shown as cross-sectional slices.

Axial (transverse) - divides the body into upper and lower; the standard CT/MRI slice.
Coronal (frontal) - divides into front and back; a face-on view.
Sagittal - divides into left and right; a side view (spine, brain, knees).

Imaging planes guide showing axial, coronal, and sagittal planes with corresponding brain images — The three principal planes describe cross-sectional views: axial separates upper and lower, coronal separates front and back, and sagittal separates left and right.

Imaging projections (mostly X-ray)

A projection describes the direction the X-ray beam travels through the patient, which changes how anatomy appears:

AP (anterior → posterior) - beam enters the front, exits the back.
PA (posterior → anterior) - beam enters the back, exits the front (a standard chest X-ray).
Lateral - taken from the side.
Oblique - taken at an angle, to open up structures that overlap on straight views.

X-ray projections guide showing AP, PA, lateral, and oblique beam directions — Projection names describe the beam path through the patient. AP and PA reverse the front-to-back direction; lateral and oblique views change the angle to separate overlapping anatomy.

The same body part can look different depending on the projection used.

Planes vs projections - not the same thing

Planes describe how the body is sliced or viewed. Projections describe how an X-ray beam passes through the body to form an image. The distinction matters once you reach image display, hanging protocols, and how acquisitions are labeled.

Key takeaway

Anatomy is structure; physiology is function; directional terms say where; planes say how the body is viewed or sliced; projections say how (chiefly X-ray) images are acquired. Together they are the clinical vocabulary running underneath every imaging system.

Continue learning

This is an orientation only. Structured training connects these terms to real images, DICOM metadata, image orientation, modality workflow, viewer behavior, and hanging-protocol logic.

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