Jugular bulb dehiscence--complete absence of a roof over the jugular bulb--is a rare malformation, probably present in <<< 1% of the general pediatric population. Of 126 children with achondroplasia evaluated in the Midwest Regional Bone Dysplasia Clinic, four and probably five, were identified as having such dehiscence (at least 3.2% of the children assessed). Identifying this increased incidence in achondroplasia is of some clinical relevance, particularly including risk of difficult to control bleeding at myringotomy. It may also present as otherwise unexplained hearing loss, tinnitus and self audible bruits in these children.