Bucket-handle is a movement of ribs that results in change in transverse diameter of the thorax.
[1] One of the most important functions of ribs and diaphragm is the change in volume of thorax that helps inspiration and expiration.
[2] In general, the ribs move around two axes.
Movement at costovertebral joints 7 to 10 about an anteroposterior axis results in raising and lowering the middle of the rib, the Bucket-handle movement.
In elevation, this increases the transverse diameter of the thorax.