Bilateral

Bilateral means "on both sides." In medicine, it describes a finding, structure, or disease that involves both sides of the body, for example, both lungs or both sides of the chest wall. It is the opposite of unilateral, which means one side only.

Origin

From the Latin bi- ("two") and lateralis ("of the side"), entering medical and anatomical usage in the 17th–18th centuries to describe paired structures and findings affecting both halves of the body.

Significance in Asbestos Context

Bilateral findings on imaging are a hallmark of asbestos-related disease. Because asbestos fibers are inhaled and distributed through both lungs, conditions like pleural plaques, diffuse pleural thickening, and asbestosis typically appear on both sides, and bilateral involvement is one of the criteria radiologists and pathologists use to attribute findings to asbestos rather than to other causes (such as a single old injury or infection, which more often produces a one-sided scar). For patients, a radiology report describing "bilateral pleural plaques" or "bilateral interstitial changes" is often a key piece of evidence linking the disease to past asbestos exposure, and it can directly support a claim under frameworks like the Helsinki Criteria.

Example Sentence

Her CT scan showed bilateral calcified pleural plaques, which her pulmonologist explained were strongly suggestive of prior asbestos exposure from her years at the shipyard.

Related Terms

Pleural Plaques, Diffuse Pleural Thickening, Asbestosis, Unilateral, Helsinki Criteria, HRCT

Notes

• Ask for and keep copies of all chest X-ray and CT reports. The words "bilateral," "calcified," and "pleural" in a radiologist's report can be important for both medical follow-up and any legal claim.
• Bilateral does not mean symmetric; one side may have much more extensive disease than the other, and that asymmetry should still be documented.
• If a report describes a finding as unilateral, ask whether prior imaging shows changes on the other side that may have been missed, since bilateral involvement strengthens the link to asbestos.
• Make sure any B-reader or pulmonologist reviewing your films specifically comments on whether pleural or parenchymal findings are bilateral, as this is a standard element of asbestos-disease attribution.