WASHINGTON — Ruth Bader Ginsburg was in her usual spot on the U.S. Supreme Court bench Tuesday, returning to the courtroom for the first time since undergoing cancer surgery in December.

She walked with her colleagues through the velvet curtains behind the bench promptly at 10 a.m., looking as fit as she did before the surgery. And, as is often her custom, she asked the first question during Tuesday's argument in a patent case.

Doctors removed a portion of one of her lungs just before the holidays after finding three cancerous lumps. As she recovered at home, she participated in the consideration and decision of the eleven cases argued in January, by reading the legal briefs and oral argument transcripts.

In mid-January, the Supreme Court's spokeswoman, Kathy Arberg, said an evaluation by doctors after the surgery found "no evidence of remaining disease, and no further treatment is required."

Ginsburg turns 86 on March 15. She has said she will remain on the court as long as her health permits.