1. 1
William 23rd Edition 2010
forceps extraction
vacuum extraction
!! ( head ,
vertex ) ( breech )
( flexion ) !!
( asynclitism )
( extension , hyperextension or face
presentation ) ( occiput )
( occiput anterior )
( occiput posterior )
( engagement )
( biparietal diameter )

2. 2
( pelvic inlet )
( sagittal suture directed anteroposteriorly )
( descent and flexion )
( descent )
( flexion )
occipitofrontal suboccipitobregma
( internal anterior
rotation )
( symphysis
pubis )
( pelvic floor )
( extension )

3. 3
occiput – bregma-
forehead – nose – mouth – chin
( external rotation )
bisacromial diameter
anteroposterior
( expulsion )