Silhouette sign

Silhouette Sign

The Silhouette Sign (pronunciation: /sɪluːˈɛt/ sign) is a radiological sign used in the field of medicine to interpret chest radiographs. It is named after the French finance minister Étienne de Silhouette, due to the shadowy outline it creates, similar to a silhouette.

Etymology

The term "Silhouette" is derived from the French language, named after Étienne de Silhouette, a French finance minister known for his hobby of creating cut-paper shadow portraits. The term "sign" in medical parlance refers to any objective evidence of a disease, which can be observed by a healthcare professional.

Definition

The Silhouette Sign refers to the loss of the normal silhouette or outline of an anatomical structure on a chest radiograph. This usually indicates that there is a pathological process, such as a mass or consolidation, obscuring the structure.

Clinical Significance

The Silhouette Sign is used to localize lesions in the chest. For example, if the right heart border is obscured on a chest radiograph, it suggests that there may be a pathology in the right middle lobe of the lung or the anterior segment of the right upper lobe. Similarly, if the left heart border is obscured, it suggests a pathology in the lingula of the left lung.

Related Terms

Chest Radiograph: An imaging test that uses X-rays to create pictures of the chest, including the heart, lungs, and chest wall.
Consolidation (medicine): A region of lung tissue filled with liquid instead of air, often due to an infection or inflammation.
Lingula: A small tongue-like projection in the left lung, analogous to the right middle lobe.