In an after coming head the following bone Is perforated during craniotomy:
Craniotomy : Consists of perforating the fetal skull, evacuating the contents and then delivering rest of the fetal pas. Indications : Delivery of dead fetus in obstructed labour with a cephalic presentation Delivery of the arrested after coming head in vaginal breech delivery Hydrocephalus Ref: Dutta Obs 9e pg 544.
Occiput
Parietal
Palate
Frontal
Abnormal labor