What is Hoover Sign?

Hoover’s sign refers to the paradoxical inspiratory retraction of the rib cage and lower intercostal

interspaces. Normally, the costal margin moves minimally during the regular respiratory cycle. However, if it does, it moves outward and upward.

It is commonly seen in COPD. However, it may also be seen in numerous other conditions (i.e congestive heart failure, asthma, severe pneumonia etc.)

It results from alterations in dynamics of diaphragmatic contraction due to hyperinflation, resulting in traction on the rib margins by the flattened diaphragm.

REFERENCES

1. Klein M: Hoover sign and peripheral airways obstruction. JPediatr 1992, 120:495-496.
2. Johnston, Chambless R et al. “The Hoover’s Sign of Pulmonary Disease: Molecular Basis and Clinical Relevance” Clinical and molecular allergy: CMA vol. 6 8. 5 Sep. 2008