Seven Cardinal Movements of Labor by Cal Shipley, M.D.

Summary

This video script, narrated by Dr. Cal Shipley, provides a detailed review of the seven cardinal movements in labor. It explains how these movements are essential for the fetus to successfully navigate the maternal birth canal. The script covers maternal pelvic anatomy, fetal stations, and describes each movement: descent, engagement, flexion, internal rotation, extension, external rotation (restitution), and expulsion. These steps ensure the fetus progresses through the birth canal, facilitating a successful delivery by aligning with the mother's anatomy, overcoming challenges like pelvic narrowing and curvature.

Takeaways

• 🧠 The seven cardinal movements in labor are crucial for the fetus to navigate through the maternal birth canal.
• 🦴 The birth canal's anatomy includes the pubic bone at the front and the sacrum at the back, creating the pelvic inlet and outlet.
• 🔄 The pelvic inlet is wider than it is deep, while the pelvic outlet is deeper than it is wide, impacting fetal movement.
• 📏 Fetal station values range from -5 at the pelvic inlet to +5 at the pelvic outlet, with 0 station at the narrow ischial spines.
• 📉 The first cardinal movement, descent, involves the fetus moving into the pelvis toward the ischial spines.
• 📍 Engagement, the second movement, occurs when the fetal head reaches the ischial spines at 0 station.
• 🤕 Flexion, the third movement, involves the fetal head adjusting to the curve of the sacrum.
• 🔄 Internal rotation, the fourth movement, aligns the fetal head with the long axis of the pelvic outlet for easier passage.
• 🧠 The fifth movement, extension, allows the fetal head to pass under the pubic bone for delivery.
• 🔁 The final two movements, external rotation and expulsion, involve the baby's head rotating back and the completion of delivery.

Q & A

What are the cardinal movements in labor?

The cardinal movements in labor are essential steps the fetus must undergo to successfully navigate through the maternal birth canal during childbirth.

How does the maternal pelvic anatomy influence childbirth?

The maternal pelvis is divided into the pelvic inlet and pelvic outlet, with the pubic bone at the front and the sacrum at the back. The shape and orientation of the pelvis influence how the fetus navigates through it.

What is the difference between the pelvic inlet and pelvic outlet in terms of shape?

The pelvic inlet is wider than it is deep, with the long axis going from left to right, while the pelvic outlet is deeper than it is wide, with the long axis running from front to back.

What is the significance of the ischial spines in childbirth?

The ischial spines represent the narrowest part of the birth canal, making it the most challenging point for the fetal head and shoulders to pass through. It is assigned a fetal station value of zero.

What do fetal stations represent?

Fetal stations are a system used to track the position of the fetus in the birth canal, with values from -5 at the pelvic inlet to +5 at the pelvic outlet. These values correspond to centimeters above or below the ischial spines.

What is the first cardinal movement, and what does it involve?

The first cardinal movement is descent, which refers to the movement of the fetal head into the pelvis, passing through the pelvic inlet and moving toward the ischial spines.

What happens during the engagement movement?

Engagement is the second cardinal movement, occurring when the fetal head reaches the ischial spines at zero station, indicating that the head is engaged in the pelvis.

How does internal rotation help the fetus pass through the birth canal?

Internal rotation is the fourth cardinal movement, where the fetal head rotates to align its long axis with the long axis of the pelvic outlet. This facilitates the passage of the head through the outlet.

What occurs during the extension movement in labor?

During the fifth cardinal movement, extension, the fetal head moves beneath the mother's pubic bone, facilitating its delivery through the birth canal.

What is expulsion, and when does it occur?

Expulsion is the seventh and final cardinal movement, occurring when the fetus is fully delivered from the mother's body, completing the process of childbirth.