Authorities say she escaped Saturday morning from 43-year-old Glenn Whittier, of Latrobe. She was taken to a hospital. Her condition wasn't immediately available.
Police say the woman told them Whittier struck her with the hammer. They say she had bite marks, cuts, bruises and a large amount of hair missing from her head.
Online court records don't list an attorney for Whittier.
He was being held Wednesday in the Westmoreland County prison. A preliminary hearing is scheduled for March 23 on charges including aggravated assault and unlawful restraint.
Copyright 2015 The Associated Press modified.