Surgical instrument for cutting through skull cap

摘要

The end edge (7) of the cylindrical drill (4) has teeth (8) cutting in both directions. The drill has a support (13) movable by a spring (19) along the drill's pivot axis between an initial position in which the support protrudes beyond the end edge, and an end position in which the end edge is released with the adjacent part of the drill. The support comprises several peripherally staggered feet (13) held on a holder (12) parallel with the drill's rotary axis. A stop (20) limits the path of the support.