Chest Lateral is a radiography positioning projection of the Thorax. Left lateral upright chest projection. SID 72". The centering point is located level of T7, 3 to 4 inches (7.5 to 10 cm) below the jugular notch; midthorax (Bontrager), on the midcoronal plane (Merrill's). The central ray is horizontal, perpendicular to IR, directed to the midthorax at the level of T7. Image-quality criteria include entire lungs from the apices to the costophrenic angles, and from the sternum to the posterior ribs, chin and arms raised enough to keep soft tissue off the lung apices. A sample technique is 120 kVp with DR 3.6 or CR 7.1 mAs, at an SID of 72 inches (183 cm).
Anatomy demonstrated
- Both lungs from apex to costophrenic angle.
- Mediastinal silhouette including heart and great vessels.
- Thoracic vertebral bodies.
- Diaphragm.
- Posterior ribs.
- Sternum in profile.
Patient preparation
- Verify patient identity using two identifiers.
- Remove all radiopaque objects from the chest area.
- Explain breathing instructions: inspiration on the second breath in, hold.
- Position patient erect, left side of chest against receptor.
- Raise both arms above the head to clear the shoulders and soft tissues.
- Weight evenly on both feet, chin up.
- True lateral: midsagittal plane parallel to the IR, coronal plane perpendicular to it.
- Center the patient to the CR and IR front to back.
Position & centering point
Level of T7, 3 to 4 inches (7.5 to 10 cm) below the jugular notch; midthorax (Bontrager), on the midcoronal plane (Merrill's).
Central ray
Horizontal, perpendicular to IR, directed to the midthorax at the level of T7.
Exposure / technique
- kVp
- 120
- mAs
- DR 3.6 / CR 7.1
- SID
- 72" (183 cm)
- Notes
- High-kVp technique. Grid required. Shows mediastinal silhouette and vertebral column. Sample technique: DR 3.6 / CR 7.1 mAs at 120 kVp, 72 in SID, for a 33 cm part (Merrill's sample chart). Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Entire lungs from the apices to the costophrenic angles, and from the sternum to the posterior ribs.
- Chin and arms raised enough to keep soft tissue off the lung apices.
- No rotation: posterior ribs and costophrenic angle away from the IR lie only slightly (about 1 cm) posterior.
- Hilar region near the center of the IR.
- Rib outlines and lung markings visible through the heart shadow.
- Diaphragm and lung markings sharp, with no motion.
Common errors
- 1 Rotation leaves the posterior ribs and costophrenic angles unsuperimposed.
- 2 Arms or chin not raised enough, so soft tissue covers the lung apices.
- 3 Posterior ribs separated well over 1 cm: the patient is rotated.
- 4 Inadequate inspiration elevates the diaphragm and obscures the lung bases.
- 5 Off-centered CR clips the lung apices or costophrenic angles.
Clinical indications
- Pathology behind the heart, great vessels or sternum, seen at 90 degrees to the PA.