Standard Chest CT Anatomical Borders
A standard chest CT scan extends from the lung apices (superior border) through the entire thorax to the upper abdomen, typically including the adrenal glands (inferior border), with lateral borders encompassing the entire thoracic cavity from skin to skin.
Superior Border
The scan begins at the lung apices, which typically corresponds to approximately 2-3 cm above the clavicles to ensure complete visualization of the upper lobes and apical pleura 1.
This superior extent is critical to avoid missing apical lung nodules, pneumothoraces, or superior sulcus tumors that may be located at the thoracic inlet 2.
Inferior Border
The scan extends inferiorly to include the adrenal glands, which typically means scanning through the upper abdomen to approximately the level of the L1-L2 vertebral bodies 1.
This inferior coverage is essential because:
- Many thoracic pathologies (particularly malignancies) can metastasize to the adrenal glands
- The costophrenic angles and posterior lung bases must be fully visualized to detect pleural effusions or basilar infiltrates
- Subdiaphragmatic pathology can present with thoracic symptoms 2
Lateral and Anterior-Posterior Borders
The field of view extends from skin to skin bilaterally, encompassing the entire thoracic cavity including the chest wall, ribs, sternum, and thoracic spine 1.
Complete visualization of the chest wall is necessary to evaluate:
- Rib fractures and bony lesions
- Chest wall masses or soft tissue abnormalities
- Subcutaneous emphysema
- Surgical hardware or monitoring devices 3
Axial Plane Orientation
- Transaxial images are displayed beginning at the superior surface progressing toward the diaphragm, with the viewer observing from below (anterior chest wall at top, patient's right on viewer's left) 4.
Clinical Pitfalls
Inadequate superior coverage can miss apical lung cancers (Pancoast tumors) or apical pneumothoraces, which are common sources of diagnostic error 3.
Insufficient inferior coverage may miss lower lobe pathology, pleural disease at the costophrenic angles, or adrenal metastases in oncology patients 1.
When evaluating trauma patients, recognize that the entire thoracic cage must be included as chest radiography misses approximately 50% of rib fractures compared to CT 3.