The sacrum is the denominator of breech and there are four positions. In anterior positions, the sacrum is directed towards the iliopubic eminences and in posterior positions, the sacrum is directed to the sacro-iliac joints. The positions are, First position - left sacro-anterior- being the commonest 2nd position - right sacro-anterior 3rd position - right sacro-posterior 4th position - left sacro-posterior Ref: Textbook of Obstetrics by D C Dutta, 6th edition, Page 376.