title: [Picture of the month. Ankylosing spondylitis].
authors.forename: J K
authors.initials: JK
authors.lastname: Christensen
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging*