During labor, we want to create more space in the pelvis with movement! Each level of the pelvis opens with different movement patterns. However, creating space in the pelvis for birth relates to the pelvis’ position. Certain pelvic positions will limit the amount of space we can create, such as more of an anterior pelvic tilt making finding internal rotation more difficult. Limited movement could result in a labor stall or arrest of labor. We can find more movement to ensure we avoid labor stalls.
But our bodies do not move in isolation, so if we cannot find certain positions in the pelvis, it could be related to the setup of other parts of our body. A big component of pelvic position is the rib cage’s position!
There are different movement patterns that open each level of the pelvis. Remember, there is not one movement that opens the entire pelvis!
These movements include:
- External rotation of the femur to create a wider space laterally in the top of the pelvis.
- Internal AND external rotation asymmetrically to open the middle of the pelvis diagonally.
- Internal rotation of the femurs to create a wider space laterally in the bottom of the pelvis.
During pregnancy, we want to ensure that these movement patterns are accessible so that we can create space in the pelvis during labor. But creating space in the pelvis is more than just opening the pelvis!
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The pelvic position influences how we can open the pelvis, and this can relate to other structures in the body such as rib positioning, low back positioning, and more!
The Rib Cage Position and its Influences on Pelvic Opening
The rib cage normally sits fairly aligned above the pelvis. The rib cage is home to the diaphragm, and its position influences the relationship between the diaphragm and the pelvic floor.
Our spines are meant to move, so the rib cage position can change in three directions:
- Front to Back: we can arch or round the upper spine
- Laterally: we can bend sideways or bring our shoulder closer to our hip on the same side
- Rotationally: we can twist and rotate in the upper back
Rib Cage to Pelvic Positional Relationships
1. Front to Back Relationship
When we round in the upper back, the pelvis tilts backward in more of a posterior tilt. We want to be able to find both front-to-back positions to influence the front-to-back diameter of the pelvic opening! If we have trouble either rounding or extending, we could limit the opening of the pelvis in this front-to-back diameter.
In the front-to-back rib cage positioning, it can influence how we can open the pelvis for birth. If the pelvis is more anteriorly tilted, which is common with a rib thrust position, we may find that external rotation is much easier to find. This would make it easier to open the top of the pelvis.
BUT internal rotation at the femur is more difficult, and we may find that opening the lower midpelvis or bottom of the pelvis is more challenging. We may appear to find internal rotation, but rather are compensating with no change to pelvic diameters. If we cannot find internal rotation, we may experience a labor stall related to the passage when baby is in the lower midpelvis. We can avoid labor stalls by finding more mobility in the rib cage, which can help us create more space in the pelvis.
Front to Back Thoracic Spine Movement Drills
2. Lateral Relationship (Side Bending)
The rib cage can also laterally bend or reach shoulder to hip. When we side bend, the pelvis usually stays in its position, but we could hike the hip towards the laterally bent side of the rib cage, as well!
With laterally bending, we may find that there becomes a rotational element to both the ribs and pelvis.
Learning to move the rib cage front to back and laterally will help us better find rotational movements in the rib cage.
And you’ll see that rotational movements can really influence pelvic opening for labor!
Side Bending Thoracic Spine Movement Drills
3. Rotational Relationship
The thoracic spine can also rotate in the transverse plane. When the rib cage rotates to the right, the pelvis rotates left. And vice versa; when the rib cage rotates to the left, the pelvis rotates left.
Then we may see more of a side bend on the side we are rotating towards. So if we rotate the ribs towards the right, we may see more of a side bend on the right side of the body, as the pelvis rotates left.
This rotational shift also influences the pelvis is more than just turning left or right, we see some torquing within the pelvis. When the pelvis is rotating left, the the right leg is more externally rotated, while the left leg is more internally rotated. This shifts the two pelvic halves, changing the space asymmetrically within the pelvis.
When opening the midpelvis, we want this rotation in the pelvis to occur so that we can create more space diagonally so baby can rotate through the pelvis. If we cannot find a rotational position of the pelvis on a certain side, say rotating to the right is really easy but to the left is more challenging in the upper spine, we may find that baby’s rotation through the pelvis is potentially compromised.
Rotational Thoracic Spine Movement Drills
Common Postural Tendencies
Most of us have the same postural tendency when it comes to the rotation of the rib cage and pelvis. We tend to be more rotated and side bent towards the right, with the pelvis, shifted with the left leg more externally rotated and the right leg more internally rotated.
In PRI, this is known as a Left AIC pattern. Our bodies are not symmetrical, our internal organs are not even symmetrical, so it makes sense that our posture favors an asymmetrical stance.
If we can understand our postural tendency, we can incorporate mobility exercises and strengthening exercises to help us find other positions. We don’t necessarily want to live in neutral since we are dynamic and meant to move, but we also don’t want to find ourselves stuck in one posture all the time!
Watch the video below to learn how our postural tendency could influence our pelvic opening for birth!
Rib Cage Position Affects Pelvic Opening!
Our bodies rarely move in isolation! Movement or positioning in one part of our body affects another portion! This in case, the rib cage position, or mobility, will influence how the pelvis is positioned. The pelvis’ position affects how we can open each pelvic level. This could affect labor in either a position or a negative way!
We can avoid labor stalls by ensuring we have the movement capability to find both internal and external rotation at the hip, which will relate to how the rib cage is positioned and can move!
If we cannot find certain positions, we may need to look beyond the pelvis and focus on the rib cage or thoracic spine!
Learn more on how to find different positions in our prenatal fitness programming, yoga courses, and webinars!