LOS ALAMITOS, Calif. — Jockey Sam Thompson Jr. died Christmas Day, five days after he was thrown from a quarter horse following a race at Los Alamitos.

The 36-year-old rider had been on life support at Los Alamitos Medical Center since the Dec. 20 accident. Thompson's family had him taken off life support Thursday, medical center spokesman Orlando Gutierrez said.

Harems Dynasty, a 2-year-old filly, threw Thompson after finishing seventh in the eighth race. The Los Alamitos Race Course season ended Dec. 21.

Thompson, who lived in Long Beach, missed much of the 2008 season because of a broken foot.

He is survived by his father, Samuel, mother Gloria, brother Eric and sister Kim.

A memorial service is planned when the 2009 season opens Jan. 2.