Genu recurvatum is a posture where the knees appear to bend backwards in standing. The recurvatum appearance is due to the knees being placed in a hyperextended position. The posture is easily identified when looking at a person from the side by the curved alignment of the legs.
From the front, recurvatum standing posture can make the kneecaps appear to point inwards. For the rest of this informative post, please head over to contributor James Speck's site, Soma Struct.