Fetal Skull Dimensions : Mnemonic

Anteroposterior Diameters

Mnemonic:

1. Larger the alphabets, larger the diameter (V>F>B)
2. Diameters with “sub” prefix are smaller than counterpart without it.

1. mento-Vertical: 14 cm
   • SUB-mento-Vertical: 11.5 cm
2. occipito-Frontal: 11.5 cm
   • SUB-occipito-Frontal: 10.5 cm
3. sub-occipito-Bregmatic: 9.5 cm
4. sub-mento-Bregmatic: 9.5 cm

Transverse Diameters

Mnemonic: MTP (Medical Termination of Pregnancy) in increasing order.

1. bi-Mastoid: 7.5 cm
2. bi-Temporal: 8 cm
3. bi-Parietal: 9.5 cm