hilar
Meaning of hilar: Hilar describes the hilum, the specific point where vessels, nerves, and airways or ducts enter and exit an organ.
Definition of hilar
Hilar is the adjective form of hilum, referring to the region of an organ where structures such as blood vessels, nerves, lymphatic vessels, and airways or ducts enter and leave. Many organs have a hilum, including the lungs, kidneys, liver, and spleen, along with individual lymph nodes.
In the lung, the hilar region is where the main airway branches, along with the pulmonary artery and veins, connect to the lung tissue, and this area is a standard reference point on chest imaging. Findings described as hilar, such as enlarged lymph nodes or a mass, are located at this junction rather than within the outer lung tissue itself.
Because the hilum concentrates so many important structures in a small area, changes there, whether enlargement, a mass, or abnormal lymph nodes, can affect multiple structures at once and often draw particular attention during imaging review.
Used in a sentence
The chest x-ray showed prominent hilar lymph nodes that prompted further imaging.
Good to know
Hilar findings on chest imaging, such as enlarged lymph nodes, can arise from infection, inflammation, or cancer, so the appearance alone does not indicate which of these is responsible.
Word origin
Where “hilar” comes from
Formed from Latin hilum, meaning a small thing or trifle, later applied to the small notch or depression where vessels and nerves attach to an organ.