Continuity: When Doctor Gloria Nathan (Lauren Velez) talks to Ryan O'Reilly (Dean Winters) about his cancerous tumour in his chest, she says that the lump is "under the left nipple". However, he was clearly bleeding from the right nipple and ever clutching the right one while in the infirmary...
Continuity: Miguel Alvarez - The large black-and-white rose tattoo on the back of the character's hand, throughout the course of the series, alternates between being on his right hand and on his left.