title: Cannon balls.
abstract: Radiological terminology includes a number of interesting and often amusing terms intended to help us understand and remember the pathological abnormality being described. What radiological sign is illustrated in Fig. 1 and what is the differential diagnosis?
authors.affiliation: Children's Hospital, Birmingham.
authors.forename: S
authors.initials: S
authors.lastname: Chapman
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D011871:Radiology / Q000379:methods*; D009626:Terminology as Topic