is a sign used to help to diagnose hydrocephalus
(accumulation of excess cerebrospinal fluid
) and brain abscesses
. Tapping (percussion
) the skull near the junction of the frontal
bones will produce a stronger resonant
sound when either hydrocephalus or a brain abscess are present.
The sign was discovered and described by Sir William Macewen (1848-1924), a surgeon and professor of the University of Glasgow, Scotland who also described Macewen's operation for inguinal hernia.