Ha's rule is related to: (A) Mechanism of Internal rotation, (B) Mechanism of Crowning, (C) Mechanism of Engagement, (D) Mechanism of Restitution
Answer is A. Elastic recoil of Levator Ani occurs bringing the occiput forwards in the midline. The process is repeated until the occiput is placed anteriorly. This is called as rotation by law of pelvic floor- Ha's rule.