Middle or Intercostal Breathing
It is better than the former but still imperfect. It is worse than low breathing and even worse in comparison to total breathing .


In the middle, or intercostal breathing, the diaphragm rises and the abdomen retracts. The ribs allow a certain extension of the rib cage. Even so, the results are still poor.

excerpt from the "MIDDLE OR INTERCOSTAL BREATHING"
of the 13th Booklet