The pace bowler was one of six batsmen to fall in the morning session as England slumped from 180 for four to 251 all out at the WACA, 134 runs behind Australia's first innings tally.
Broad failed to come out to the field after the lunch break for the start of Australia's second innings and England team officials said he had been taken for a scan after experiencing discomfort trying to bowl a couple of deliveries in the nets.
The Englishman had been dismissed lbw by a Mitchell Johnson delivery that struck him low on the leg but it was unclear whether that was responsible for the injury.
Broad, England's best bowler in the ongoing series, missed the last three matches of the 2010-11 Ashes series in Australia through injury.
Australia lead the five-match series 2-0 and England need at least a draw in Perth to keep the series alive.
Image: Stuart Broad
Photograph: Ryan Pierse/Getty Images
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