Shop worker Lena Tocher was nearly 20 stone, “due to an over-active thyroid”, when the accident happened last November.
She was on her way home from work at a frozen food store when the bus mounted the pavement and hit her.
Her survival is thought to be also partly due to the fact that there was a window recess at the point where the accident occurred, which the top half of her body could lean into.
The 44-year-old mother-of-two, from Crieff, was taken to intensive care following the horrific accident, which took place at 3.40pm on 6 November in the Perthshire town’s Broich Road as she made her way home from work at Wiltshire Farm Foods.
She suffered major crush injuries, including lacerated kidneys and liver, a broken femur, shattered pelvis, bruised and bleeding heart and broken bones in her back.
She was put in a coma and said she feels she is lucky to be alive.
She said: “I was 19-and-a-half stone when it happened and had just been diagnosed with an underactive thyroid two days before.
“I was told if it wasn’t for my weight I wouldn’t be here.”
She continued: “I saw the bus coming but it happened so quickly that I couldn’t do anything about it. I know it was the corner of the bus that hit me because I remember hitting on the driver’s window and the passenger door to tell him.
“I was going in and out of consciousness and remember lots of people around me.
“I remember coughing and seeing blood and asking whose blood is that.”
She is still being looked after at Crieff Cottage Hospital and is on “a slow road to recovery”.
She said: “I was told I would never walk again but I can now walk a short distance on crutches
“My goals were to be able to wash and dress myself and be able to transfer myself in the wheelchair so that I wouldn’t be a burden and I have managed to do that.”
Her son John, 14, daughter Sabrena, 20, and husband Ian can visit her whenever they want.
Local residents have asked for improvements to road safety at the point where the accident occurred.