THIS is the tragic final picture of a 12-year-old girl grasping her sister's hand shortly before she succumbed to her injuries from a quad bike crash.

Riley Robinson suffered horrid injuries when she lost control of the vehicle and smashed it into a tree on her grandmother's property in Michigan, US, with her sister Peyton, 14, on the back.

The image of them lying side by side in hospital, covered in casts and bruises from the crash, was taken just hours before Riley passed away last month.

Her family remembered her as "very caring" and even in death, her organs went to save the lives of six children she did not know.

Her dad Larry said: "I think the hardest thing we did was signing the paper for organ donation.

"I don't get our daughter back but there are six families that get a little more time to spend with their love ones.

"Life as you know it can be over in a blink of an eye... She [Riley] was the life of the party. Trusting, very caring."

Riley lost control on rough terrain and went into a tree at high speed on the morning of Sunday, September 9.

Their brother Tyler, 16, found them after the crash, picked the four-wheeler off his sister and called an ambulance.

The schoolgirls were then airlifted to a hospital in Grand Rapids but Riley died from her injuries.

Her sister Peyton also suffered bad injuries including fractures to her arms, elbow and shoulder.

She will undergo facial reconstructive surgery to fix her eyes, jaw and nose, Fox 2 reported.

Michigan law says under-16s must take a safety course before driving an ATV and must always wear helmets.