She tried to escape me but the back of her knees hit the bed.

I felt the couch at the back of my knees.

She put her feet in the backs of his knees.

When next he began, they were on the backs of her knees.

I am 45 and have been suffering from pain at the back of my left knee.

She had a suck mark on the back of her knee.

The two soldiers kicked the back of the young man's knees to take him down.

I aimed my right shoulder at the back of his knees.

His fingers slid up to the back of her knees.

Fired and put a bullet through the back of the guy's knee.