If you could look past her long wiry red hair and thick black skin, Suma looked very similar to the human patients Dr Kevin Moriarty and Dr Marinis Pirpiris usually care for.

The female orangutan's heart, lungs and bones generally resemble those of humans, especially when her skeleton is captured on an X-ray machine.

Suma the orang-utan was on the table for three hours while the team X-rayed her arthritic joints and checked her heart rate, brain activity and blood pressure. Credit:Justin McManus

But unlike her more evolved relatives, the primate's hips rotate almost 360 degrees so she can swing through trees. The 50-kilogram ape is also more prone to attack if she wakes too soon from an anaesthetic.

On Thursday, recently retired anaesthetist Kevin Moriarty and Epworth orthopaedic surgeon Marinis Pirpiris volunteered their time to assist vets at Melbourne zoo with an examination of Suma, 37, who has been showing signs of arthritic pain on her left side since 2013.