title: Reply to Dr Barton.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Sites
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Neal
mesh_terms: D001917:Brachial Plexus / Q000000981:diagnostic imaging*; D006801:Humans; D009407:Nerve Block / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods*