Nishaabout 2 years ago

Station of the head in relation to ischial spines

Spines are the most prominent bony projections felt on internal examination and the bispinous diameter is the shortest diameter of the pelvis in transverse plane being 10.5 cm. The level of ischial spines is the halfway between the pelvic inlet and outlet. This level is known as station zero (0). The levels above and below the spines are divided into fifths to represent centimeters. The station is said to be 'O' if the presenting part is at the level of the spines. The station is stated in minus figures, if it is above the spines (-1 cm, -2 cm, -3 cm, -4 cm and -5 cm) and in plus figures if it is below the spines (+1cm,+2cm,+3cm,+4cm,+5cm).