Castell's sign

The presence or absence of splenomegaly, however, can be reliably appreciated on physical exam using Castell's sign in conjunction with other clinical information, increasing the positive predictive value of the test.

The resonant note heard upon full expiration is likely to be due to the air-filled stomach or splenic flexure of the colon.

If the spleen is enlarged enough that the inferior pole reaches the eighth or ninth intercostal space, a dull percussion note will be appreciated, indicating splenomegaly.

First the presence of gross splenomegaly or profuse fluid in the stomach or colon may lead to the absence of a resonant percussion note on full expiration.

Also, later articles have criticized the maneuver's reliability as befalling to more obese individuals and the amount of time the patient is post-prandial.

[3] Grover et al., recommends a greater than 10% preexamination clinical suspicion of splenic enlargement to effectively rule in the diagnosis of splenomegaly with physical exam.