When the head is flexed well, suboccipitobregmatic & the biparietal diameter present. Vertex- This is bounded by posterior fontanelle, 2 parietal eminences & by the anterior fontanelle.The skull is divided into 3 parts with obstetrical importance. It closes by 6 weeks of age.Īnd the other 2 with less obstetrical significance is anterolateral (Sphenoid) and posterolateral fontanelles (Mastoid). This is situated at the junction of the lambdoidal and sagittal sutures. Posterior Fontanelle / Lambda- (shape greek like λ ) It is broad kite-shaped and it measures 3-4 cm long and 1.5-2 cm wide and normally closes by 18 months. This is found at the junction of sagittal, coronal, and frontal sutures. Where 2 or more sutures meet, a fontanelle is formed. Squamous suture- Lies between the temporal and parietal bone.Frontal suture- This runs between the 2 halves of the frontal bone.Coronal suture- This separates the frontal bone from the parietal bone passing from one temple to another.Sagittal suture- Lies between 2 parietal bones.Lambdoidal suture- This separates the 2 parietal bones from the occiput bone.Sutures are cranial joint & formed where 2 bone adjoins.

In addition to these 5, the upper part of the temporal bone is flat and forms a small part of the vault. At the center of each is the frontal eminence.

Lies on either side of the skull, ossification center of each called the parietal eminence. At the center is an occipital protuberance. Part of it contributes to the base of the skull, as it contains the foramen magnum, which protects the spinal cord as it leaves the skull. Lies at the back of the head & forms the region of occiput. The head is the most difficult part to be born whether it comes first or last. It contains a delicate brain that is large in relation to the fetal body & in comparison with the mother’s pelvis, therefore, some adaptation between skull & pelvis must take place during labour.

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