R&B singer / songwriter Jason Derulo is being forced to cancel his scheduled UK tour after fracturing a vertebrae during rehearsals this week in Miami.  According to a statement from Derulo's label, he was attempting an acrobatic move when he landed on his head, injuring his nexk in process.  Derulo posted a photo of himself online, in which he's laying on a hospital bed wearing a neck brace.  The UK leg of Derulo's Future History World Tour was slated to kick off Febraury 23rd in Glasgow and wrap up March 3rd in Newcastle.