Health Scare for Serena Williams

Serena Williams has undergone emergency surgery for a blood clot on her lung, complications from a pulmonary embolism.  

The tennis great tweeted from the hospital: "Tough day...."

Earlier this week, Williams seemed fine as she walked the red carpet at the Vanity Fair Oscar® party:
Her leg had been in a cast for seven months before she suffered the pulmonary embolism