Mechanism of labour - the interaction between the maternal pelvis and fetal skull.

This article considers the anatomy and physiology underpinning the mechanism of labour in terms of the amazing journey the fetus completes through the maternal pelvis. In order to monitor maternal and fetal wellbeing and promote progress in labour, the midwife needs a thorough understanding of: the maternal pelvis, the external structure of the fetal skull, and how the presentation and attitude of the fetus determines the presenting diameter of the skull.