Las espátulas de Thierry

Abstract

Spatulas are two simetric, independent, thin and solid non-fenestrated levers. They work by pushing and not by pulling, as forceps does, providing, at least in theory, a good protection fetal head. They have been sparsely spread. The rotatation and descend of the head are made whith forceps by pulling, so that the head needs to come into play with the instrument. Spatulas, however, provide a propulsion from up above, so there is a free descend of the head. So, in forceps exists the principle of solidarity and in spatulas, the movility one. Using forceps, the work is done by pulling and dragging fetus downward. However, spatulas, workig as a first grade lever, push the head from up above to outside down, detaching both sides of the tissues outside. On the other hand, forceps pullss the head caught into spoons and reject soft parts till the base, stretching them.