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Mnemonics, Simplified Concepts & Thoughts

fetal skull transverse

Fetal Skull Dimensions : Mnemonic

Epomedicine, Jul 27, 2018

Anteroposterior Diameters

Mnemonic:

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

fetal skull AP

  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

fetal skull transverse

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
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PGMEE, MRCS, USMLE, MBBS, MD/MS AnatomyObGynReproductive system

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Comments (6)

  1. Tajmina parbin says:
    Sep 7, 2019 at 9:10 am

    Very useful information

    Reply
  2. samikshya lama says:
    Jan 21, 2020 at 3:52 pm

    why is submentovertical diameter less than mentovertical

    Reply
    1. Taha says:
      Nov 27, 2020 at 3:30 pm

      Because it is measured from a closer point to the back of the head.

      Reply
    2. Dr Ankit says:
      Mar 20, 2021 at 2:11 am

      Bcz it is made by God n we can not change it

      Reply
    3. lakshmi says:
      Jun 11, 2023 at 11:05 pm

      submento is from the side of the chin to vertex.so that is why it is smaller than mento vertical.

      Reply
  3. Dushyant says:
    Nov 24, 2021 at 7:28 am

    Pic is informative, could have been more clear graphically

    Reply

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Epomedicine. Fetal Skull Dimensions : Mnemonic [Internet]. Epomedicine; 2018 Jul 27 [cited 2025 May 9]. Available from: https://epomedicine.com/medical-students/fetal-skull-dimensions-mnemonic/.

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