Fetal position & pelvisFree in the app
Fetal skull diameters
Which diameter presents depends on flexion.
Source: GFMER · textbooksDiameter
| Suboccipitobregmatic | 9.5 cm — well-flexed vertex (OA). |
|---|---|
| Suboccipitofrontal | 10 cm — partly flexed vertex. |
| Occipitofrontal | 11.5 cm — deflexed vertex / OP. |
| Mentovertical | 13–13.5 cm — brow (too big to engage). |
| Submentovertical | 11.5 cm — partly extended face. |
| Submentobregmatic | 9.5 cm — fully extended face. |
| Biparietal | 9.5 cm — widest transverse. |
| Bitemporal | 8 cm. |
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