Page 61 - 33Elctronic Book (3) Normal Labor

The head may become so flexed that the chin is brought into closer contact with the

fetal chest (ascent of the sinciput and descent of the occiput)

As the consequences, the smallest antero-posterior diameter (the suboccipito-

bragmatic diameter )is presented into the pelvis.

4-Internal rotation of the head:

▪ The head enter the pelvis in the transverse or diagonal position. When it

reaches the pelvic floor, the occiput is rotated and lies beneath the symphysis

pubis.

5-Extensionof the head:

▪ When the fetal head reaches the perineum for birth. The occiput passes

under the lower border of symphysis pubis first, and then the head emerges

by extension: First the occiput, then the face, and finally the chin.

6-Restitution.

After delivery of the head, the occiput rotates one eighth of a circle in a direction

opposite to that of internal rotation to undo the twist of the neck caused by internal

rotation.

7-External rotation:

The occiput undergoes another external rotation one-eighth of a circle in the same

direction as that of restitution this is due to internal rotation of the anterior shoulder

one- eighth of a circle. This movement is transmitted to the delivered head. So at the

end the occiput is towards one thigh and the face is towards the outer thigh.

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