Radiographic Techniques - Thoracic Vertebrae

Radiographic Techniques - Thoracic Vertebrae

• Landmarks:
  • The inferior angle of the scapula marks the level of T7 (when arms are at sides).
  • The sternal notch is at the junction of T2 and T3.
  • The sternal angle indicates T4, while T9 corresponds to the xiphisternal junction. Xiphisternal joint is variable in size.
  • The lower costal margin identifies L3, an easily recognizable landmark for spinal radiography positioning.
  • A line through the superior iliac crests indicates L4.
  • The tubercle of the iliac crest locates L5.
  • Anterior and posterior iliac spines are at the level of the second sacral vertebra.
  • Cricoid cartilage is at the level of the sixth cervical vertebra.

Anteroposterior Radiography (Basic)

• Patient Position: Patient supine on the X-ray table, with the median sagittal plane perpendicular to the table and centered with the Bucky.
• Cassette Positioning: The upper edge of the cassette should be just below the thyroid cartilage prominence to include upper thoracic vertebrae.
• Beam Direction: The collimated beam is centered at right angles to the image receptor and 2.5 cm below the sternal angle, aimed precisely at the spine.

Lateral Radiography (Basic)

• Patient Position: Commonly taken in lateral decubitus, but can also be erect.
• Image Receptor Alignment: The median sagittal plane should be parallel to the image receptor and the midline of the axilla, coincident with the table or Bucky midline.
• Arm Positioning: Arms should be raised well above the patient's head.
• Head Support: The head can be supported with a pillow.
• Cassette Positioning: The upper edge of the cassette should be 3-4 cm above the spinous process of C7.
• Beam Direction: The collimated vertical beam should be at a right angle to the long axis of the thoracic vertebrae; this may require caudal angulation.
• Beam Centering: Beam is usually centered just below the inferior angle of the scapula (easily palpable), assuming arms are raised.

Essential Image Characteristics (General)

• Vertebrae Range: The image should include vertebrae from C7 to L1.

• Image Density: Adequate density for clear visualization of bony details of upper and lower thoracic vertebrae is crucial.

• Shoulder Superimposition: Upper two or three vertebrae may be obscured by shoulder superimposition.

• Rib on L1: Absence of a rib on L1 at the lower border of the image confirms proper inclusion of T12 in the field.

• Patient Rotation: Superimposed posterior ribs indicate the patient was not rotated too far forward or backward.

• Image Density for Diagnosis: Sufficient image density is necessary for accurate diagnosis.

• Common Faults and Solutions:

  • Inadequate upper thoracic vertebrae on the image: Image receptor and beam may be centered too low, omitting these vertebrae from the image.
  • Missing lower vertebrae: Lower vertebrae (especially L1) may be excluded from the image. L1 is easily identified due to typically not having a rib attached.

• Radiographic Contrast: High radiographic contrast may cause high density over the vertebrae. Lower contrast produces acceptable density for both upper and lower vertebrae (see Fig. 6.17c and 6.17d).