Radiographic positioning terminology

Radiographic positioning terminology is used routinely to describe the position of the patient for taking various radiographs. Standard nomenclature is employed with respect to the anatomic position.

Terminology

Basic terms of relations

• anterior is towards the front of the body (Latin: before)
• posterior is towards the back of the body (Latin: after)
• superior is towards the top of the body (Latin: above)
• inferior is towards the bottom of the body (Latin: below)
• medial is towards the midline (Latin: middle)
  • compared with median which is in the midline rather than towards the midline
• lateral is away from the midline (Latin: side)
• proximal is towards the centre of the body (Latin: near)
• distal is away from the centre of the body (Latin: far)
• superficial is towards the surface of the body
• deep is away from the surface of the body
• ipsilateral is on the same side of the body
• contralateral is on the opposite side of the body

Planes

• the axial plane (transverse or transaxial plane): horizontal plane perpendicular to the long axis of the body
  • divides the body into superior and inferior parts
• the sagittal plane: vertical plane parallel to the median plane (or midsaggital plane)
  • divides the body into right half and left halves
• the coronal plane: vertical plane perpendicular to the median plane
  • divides the body into anterior and posterior parts

Body positions

• erect: either standing or sitting
• decubitus: lying down
• supine: lying on back
• Trendelemburg position: the patient is supine (on an inclined planeradiographic table) with the head lower than the feet
• prone: lying face-down
• lateral decubitus: lying on one side
  • right lateral: right side touches the cassette
  • left lateral: left side touches the cassette

Movement

• flexion: decrease in the angle of the joint
• extension: increase in the angle of the joint
• abduction: movement of limb away from midline
• adduction: movement of limb towards the midline
• pronation: movement of hand and forearm to bring the palm facing posterior
• supination: movement of hand and forearm to bring the palm facing anterior
• circumduction: circular movement of a joint using a combination of flexion, abduction, extension and adduction such that the distal limb describes a circle
• opposition: thumb brought to oppose another digit
• reposition: thumb repositioned back to the anatomic position
• elevation: movement of the scapular superiorly
• depression: movement of the scapular inferiorly
• eversion: movement of the sole of the foot away from the median plane
• inversion: movement of the sole of the foot towards from the median plane
• protrusion: movement of the mandible, lips or tongue anteriorly
• retraction: movement of the mandible, lips or tongue posteriorly

Projections

• antero-posterior (AP): central ray passes, perpendicular to the coronal plane, from anterior to posterior
• postero-anterior (PA): central ray passes, perpendicular to the coronal plane, from posterior to anterior. Depending on the anatomic segment to radiograph, synonyms can be used, for example: occipito-frontal (skull); dorso-ventral (thorax); dorso-palmar (hand)
• lateral: central ray passes from one side of body to the other through the axial plane
• oblique: central ray passes through the body/body part through a plane which is at an angle to the transverse plane/coronal plane
• axial: central ray passes through (or parallel) to the long axis of the body. In some cases, however, the central ray runs through (or parallel) to the long axis of the skeletal segment studied (for example, the axial view of the calcaneus).