Obstetric and Gynecological Nursing - The Carter Center

Echanism of Labour in a Normal Vertex Presentation
Position- Left OcciputoTransverse
Lie -Longitudinal
Attitude- Flexion
Presentation-Vertex
Position- Left occiputo transverse
The head engages the pelvis with the Sagital suture in the
transverse diameter of the pelvic brim
1. Flexion and descent of the head: The head descends with
increasing flexion; the occiput reaches the pelvic floor
first.
2. Internal Rotation of the head: (Whatever reaches the
pelvic floor first must rotate forwards). As the occiput
reaches the pelvix floor it rotates anteriorly.
3. Crowing of the head: The occiput escapes under the
symphysis put and the head no longer recedes between
uterine contractions.
4. Extension of the head: The face sweeps the perineum
and the head is born by extension.
5. Restitution of the head: This is the turning of the head to
undo the twist in the neck that took place during internal
rotation of the head.
6. Internal rotation of the shoulders: Meanwhile the
shoulders have entered the brim in the oblique diameter,
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