This document describes the mechanism of labor for breech births. It explains that delivery occurs in three stages: 1) delivery of the breech (buttocks and lower limbs), which involves engagement, descent, flexion, internal rotation and birth of the buttocks; 2) delivery of the shoulders and arms, through engagement, descent, internal rotation, and birth of the shoulders; and 3) delivery of the head, through engagement, descent, flexion, internal rotation and birth of the head. Each stage involves the baby engaging and descending through the pelvis, rotating internally, and flexing to be born.

1. Mechanism of labour in breech
Amarendra B. Singh
090201263

2. Positions
* Left sacro-anterior.
* Right sacro-anterior.
* Right sacro-posterior.
* Left sacro-posterior.
* Left and right sacro- transverse (lateral).
* Direct sacro-anterior and posterior.
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4. Mechanism of labour
• Delivery of the breech (Buttocks and lower
limbs)
• Delivery of the shoulders and arms
• Delivery of the head
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5. Delivery of lower limbs and
buttocks
• Engagement
• Descent
• Flexion
• Internal rotation
• Birth of Buttocks
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6. Delivery of the buttocks
* The engaging diameter is the
bitrochanteric diameter 9.5cm which
enters the pelvis in one of the oblique
diameters.
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7. The anterior buttock meets the pelvic floor
first so it rotates 1/8 circle anteriorly .
* The anterior buttock hinges below the
symphysis
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8. and the posterior buttock is delivered first by
lateral flexion of the spines followed by the
anterior buttock.
* External rotation occurs so that the sacrum
comes anteriorly.
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9. Delivery of shoulders and arms
• Engagement
• Descent continuous
• Internal rotation
• Birth of shoulders
• Restitution
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10. Delivery of the shoulders
* The shoulders enter the same oblique
diameter with the bisacromial diameter 12
cm (between the acromial processes of
the scapulae).
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11. • The anterior shoulder meets the pelvic
floor first, rotates 1/8 circle anteriorly,
hinges under the symphysis, then the
posterior shoulder is delivered first, the
baby is then lowered and the anterior
shoulder and arms pass out under the
symphysis.
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12. Birth of after coming head
• Engagement
• Descent
• Flexion
• Internal rotation
• Birth of the head
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13. • Descent and Engagement: The head
enters the pelvis in the left oblique
diameter. The occiput is in the right
anterior quadrant of the pelvis.
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14. • Flexion: It is important that flexion is
maintained.
• Internal rotation: The head strikes the pelvic
floor and rotates internally so that sagittal
suture comes to lie in anteroposterior
diameter.
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15. • Birth of the head by flexion: The nape of
the neck pivots under the symphysis and
the chin, mouth, nose, forehead, bregma,
and occiput are born over the perineum by
a movement of flexion.
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