Britney Spears jaydenseanbite.jpg

Us quotes a source who says that the bruise Jayden was treated for the night Britney went to the hospital, actually came from his brother Sean.

After noticing Brit's younger son's injuries, police were informed by Federline's bodyguard, (at the house to pick up the boys) that "the injuries were on Jayden before the child had even arrived at Spears' home earlier in the day, and that his older brother, Sean Preston, had actually bit him."

We're certainly relieved to know the marks just came from some sibling horseplay rather than anything that happened in last Thursday's fracas!