Recovery position or left lateral recumbent position.
The dorsum is medical terminology for the back. Hence, the dorsal position is lying on your back.
Guy is lying on his back with his knees bent up and feet on the bed. Girl is lying on her back on his body with both legs bent in the air.
Ankylosed is the medical term meaning abnormally bent; flexed is the medical term meaning normal bending of a joint.
in a bent position
You should place a casualty with an abdominal wound in a comfortable position lying on their back with knees bent to reduce strain on the abdomen. Avoid giving them anything to eat or drink to prevent further complications. Seek medical help promptly.
Supple means that they are flexible or easily bent, i.e. not stiff.
Flexion
The medical terminology combining form for stiffness, bent or crooked is "ankyl/o".
Mostly called "back lying position". Lay flat on back with your knees flexed/bent upwards with your feet laying flat on the bed. This position is used for medical exam's of vaginal & rectal. Sometimes used for comfort measure or exercise. Rhianna Berriman
Different people approach lying in bed differently. Some people like to lay on their side, with their knees bent. Others like to lay on their back facing the ceiling. Having a pillow between the knees while on the side, or having one under the knees while on the back will help with sleep posture.
The medical term for bent backward is "hyperextension." This occurs when a joint is extended beyond its normal range of motion, leading to potential injury or strain.
bent knees ---- a lap