<Tr> <Th> 93 </Th> <Td> 15 </Td> <Td> "Before and After" </Td> <Td> Dan Attias </Td> <Td> Tony Phelan & Joan Rater </Td> <Td> February 12, 2009 (2009 - 02 - 12) </Td> <Td> 15.70 </Td> </Tr> <Tr> <Td_colspan="7"> <P> Addison (Kate Walsh) arrives with her brother Archer (Grant Show), who has worms in his brain . Cristina learns of Owen's pre-Iraq past and Bailey considers a pediatric surgery fellowship . Izzie enlists the help of the attendings and her fellow residents in a game to boost camaraderie amongst the interns, and George finds out that Sadie is behind with her skills, forcing her to make a decision . Derek and Mark spend the evening reminiscing on their med school days with Addison, Naomi Bennett, and Sam Bennett . </P> This episode begins a crossover with Private Practice that concludes on "Ex-Life". </Td> </Tr> <P> Addison (Kate Walsh) arrives with her brother Archer (Grant Show), who has worms in his brain . Cristina learns of Owen's pre-Iraq past and Bailey considers a pediatric surgery fellowship . Izzie enlists the help of the attendings and her fellow residents in a game to boost camaraderie amongst the interns, and George finds out that Sadie is behind with her skills, forcing her to make a decision . Derek and Mark spend the evening reminiscing on their med school days with Addison, Naomi Bennett, and Sam Bennett . </P> <Tr> <Th> 94 </Th> <Td> 16 </Td> <Td> "An Honest Mistake" </Td> <Td> Randy Zisk </Td> <Td> Peter Nowalk </Td> <Td> February 19, 2009 (2009 - 02 - 19) </Td> <Td> 15.39 </Td> </Tr>

Grey's anatomy season 5 episode 19 guest stars