Two Northern Ireland doctors have helped rescue a young woman from the "death zone" on the world's highest mountain.
Top of the world: Nigel Hart on Mount Everest
Roger McMorrow, 34, from Lisburn and Nigel Hart, 41, from Belfast helped save Nepalese climber Usha Bista, 22.
The young woman was found lying alone and unconscious on the approach to the summit of Mount Everest.
The doctors were part of a research team, coordinated by University College, London, examining how the human body responded to extreme conditions.
They had set up the world's highest medical laboratory on Everest's South Col.
But their lifesaving skills were put to immediate use when Usha, who had collapsed and was suffering from oxygen deprivation, was found lying on the mountain on 21 May at an altitude of 8,500 metres above sea level.
Nigel Hart and Roger McMorrow were part of the research team
She has now recovered after being treated for frostbite.
Medical team leader Dr Mike Grocott said: "This wasn't that we intended to get involved in, but something where we were compelled to help with when the situation arose."
He added: "She had an inadequate amount of oxygen - probably only one cylinder, which is really not enough to get to the top of Everest and back again.
"She developed something called high-altitude cerebral oedema due to low oxygen levels."
Dr Hart and Dr McMorrow both reached the summit of Everest last week, shortly after dentist Hannah Shields, also from Northern Ireland, scaled the mountain.