HAVANA – Cuban President Fidel Castro’s advancing age was brought home Thursday after he fractured a knee and arm when he tripped and fell at a public event.

The 78-year-old leader has played a larger-than-life role in Cuba’s communist society for more than four decades. Castro’s elderly brother is his designated successor.

“I’m all in one piece,” Castro declared on state television Wednesday night after tripping on a concrete step while returning to his seat after an hour-long speech in the central city of Santa Clara.

A medical examination early Thursday confirmed Castro suffered a broken left knee and a hairline fracture in his upper right arm, said an official notice carried by state media.

Castro’s tumble – captured by Associated Press Television News, but not shown by state television cameras – was sure to cause speculation about the communist leader’s health after 45 years of ruling this island of 11.2 million people.

Castro’s health has long been closely watched – particularly by his political enemies in Miami, home to a large Cuban exile community.