In human anatomy / biomechanics, what is the motion called when the arm swings sideways so the elbow moves in an arc of 90 degrees? In human anatomy / biomechanics, what is the motion called when the arm swings sideways so the elbow moves in an arc of 90 degrees? So e.g. if a person was to elbow somebody behind them , or if somebody had their arm out and then swung it keeping it parallel with the floor. Like in this video <

It’s humeral retroversion at a 90 degrees abduction angle with extended elbow and slightly internally rotated shoulder.