A woman suffered spinal injuries after being run down by a car driven by her brother in an alleged domestic incident at Winmalee yesterday (Wednesday).
Police will allege the 19-year-old woman was involved in an argument with her 20-year-old brother at a Heather Road home about 2.30pm after her cat urinated on the man's computer.
"Police will allege the woman was dragged across the floor and her cat thrown into her brother's car," a police statement said.
"The woman was then struck by the man's car as it drove along Heather Road outside the home."
The woman suffered a fractured spine, fractured leg and a collapsed lung in the incident, and remains in a serious condition in Nepean Hospital.
A crime scene was established at the scene and the man was arrested. He has been charged with assault and negligent driving, and was bailed to appear before Penrith Local Court on May 15.
The cat was uninjured in the incident, police said.