Overview
This lecture reviews essential radiographic positioning terminology, focusing on body positions, projections, and anatomical reference terms crucial for understanding imaging procedures.
Position vs. Projection
- Position refers to the specific orientation or placement of the patient's body (e.g., supine, prone, erect, recumbent).
- Projection describes the path of the X-ray beam, from entry to exit through the body (e.g., PA, AP).
Common Body Positions
- Supine: Lying on the back, facing upward.
- Prone: Lying on the stomach, facing downward.
- Recumbent: General term for lying down, regardless of side.
- Erect/Upright: Patient stands or sits vertically.
- Trendelenburg: Lying down with head lower than feet.
- Fowler's: Lying down with feet lower than head.
- Anterior Position: Anterior side against the board.
- Posterior Position: Posterior side against the board.
Lateral and Oblique Positions
- Lateral Position: Side closest to the image receptor names the lateral (e.g., right lateral—right side closest).
- Oblique Position: Patient is rotated; named by the side/part closest to the image receptor (e.g., right anterior oblique).
Decubitus Positions
- Decubitus: Lying down with a horizontal beam; used to detect air/fluid levels.
- Dorsal Decubitus: Back down, horizontal beam.
- Ventral Decubitus: Front down, horizontal beam.
- Lateral Decubitus: Named for side down (e.g., left lateral decubitus).
Types of Projections
- PA (Posteroanterior): Beam enters posterior, exits anterior.
- AP (Anteroposterior): Beam enters anterior, exits posterior.
- Axial: Beam travels along body’s long axis.
- Tangential: Beam skims a body surface or part.
Anatomical Position & Planes
- Anatomical Position: Body facing forward, palms out.
- Body Planes: Sagittal/mid-sagittal (divides left/right), coronal/mid-coronal (divides front/back), transverse (divides top/bottom), oblique (angled).
Key Terms & Definitions
- Anterior (Ventral) — Front surface of the body.
- Posterior (Dorsal) — Back surface of the body.
- Proximal — Closest to body’s midline or origin.
- Distal — Farthest from midline or origin.
- Cephalad — Toward the head.
- Caudad — Toward the feet.
- Internal Rotation — Rotating toward body center.
- External Rotation — Rotating away from body center.
- Pronation — Palm down.
- Supination — Palm up ("holding soup").
- Abduction — Movement away from body.
- Adduction — Movement toward body ("adding to body").
Action Items / Next Steps
- Review and memorize surface landmark levels (e.g., mastoid tip at C1, iliac crest at L4-5).
- Understand and differentiate body habitus types (asthenic, hyposthenic, hypersthenic).
- Make flashcards for all key terms and anatomical landmarks.
- Review body planes and anatomical terminology from A&P courses.