US Supreme Court judge Ruth Bader Ginsburg has fractured three ribs after a fall on Wednesday, the court says, BBC reports.
The fall happened in her office at the Supreme Court in Washington.
Ms Ginsburg, 85, went home but was in discomfort and went to George Washington University hospital on Thursday morning, a statement said.
Tests showed that she had fractured three ribs on her left side and she has been admitted for observation and treatment.
It means Ms Ginsburg - the most senior justice on the court's liberal wing - will not be present for Thursday's investiture of Brett Kavanaugh, whose appointment led to protests following allegations of sexual misconduct.
The appointment, confirmed last month by the Senate, restores the nine-member court's conservative majority. The court has the final say on issues such as abortion, gun control and voting rules.