Police have ruled out drugs or alcohol as the cause of Jamie Lynn Spears' boyfriend CASEY ALDRIDGE's car crash this weekend (26Apr09).
Aldridge, who has a young daughter with Britney Spears' little sister, was airlifted to the emergency room after he swerved into a ditch while driving down a Louisiana highway in the early hours of Sunday (26Apr09).
It has since emerged that three of the five people riding in the truck - including Aldridge himself - were thrown from the vehicle as it flipped over.
The 20-year-old suffered mild brain trauma and a fractured skull, while another passenger sustained a broken collarbone, and a third injured his hip, reports TMZ.com.
Jamie Lynn has rushed to Aldridge's bedside as doctors keep him under observation at the University of Mississippi Medical Center.
Following the crash, he was slapped with a misdemeanour charge of careless operation of a vehicle - but authorities have declared there was no indication he was drunk or on drugs at the time of the crash.
Aldridge had attended a cousin's bachelor party prior to the accident.