This is a chapter 2.1 summary of “Recognizing and Treating Breathing Disorders” by Leon Chaitow.
You’re Writing About DNS???!!??!
Yes, I am.
Pavel Kolar and crew actually contributed to quite a few chapters in this edition, and this one here was overall very well written. Believe it or not, it even had quite a few citations!
Why they don’t cite many references in their classes is beyond me, but that’s another soapbox for another day. Onward to a rock-solid chapter.
En utero, the diaphragm’s origin begins in the cervical region, which could possibly have been an extension of the rectus abdominis muscle. As development progresses, the diaphragm caudally descends and tilts forward. When the child is between 4-6 months old, the diaphragm reaches its final position.
Throughout this period, the diaphragm initially is used for respiratory function only. As we progress through the neonatal period (28 days), we see the diaphragm progress postural and sphincter function.
The diaphragm is integral for developing requisite stability to move. Achieving movement involves co-activation of the diaphragm, abdominal, back, and pelvic muscles. This connectivity assimilates breathing, posture, and movement. If this system develops properly, we see the highest potential for motor control.
The largest developmental changes in this system occur at 3 months. Here we see the cervical and thoracic spine straighten and costal breathing initiate. 4.5 months show extremity function differentiation, indicating a stable axial skeleton to which movement may occur.
Further progression occurs at 6 months. Here costal breathing is fully established. We also have increased diaphragm and lumbar spine stability. This part is necessary for support to occur in the quadruped position, as the proximal attachment of the psoas has a firm place to pull the baby up onto palms and thighs.
In an Ideal World
Per development, an ideal breathing pattern ought to involve the diaphragm descending in the caudal direction, with elastic recoil promoting ascension upon exhalation. As a result, the organs shift caudally as well, and the abdominal wall expands in all directions.
From a muscular perspective, we see an alternating dance of muscle activity. Inspiration requires concentric diaphragm and pelvic floor activity, which compresses the abdominal cylinder to establish intra-abdominal pressure. Ab wall expansion occurs via eccentric activity of the abdominal muscles, quadratus lumborum, spinal extensors, and hip external rotators. When we exhale, the reverse occurs: diaphragm and pelvic floor eccentrically return to their starting position and the ab wall concentrically tightens up.
Regarding the ribs, we can break them up into segments that do or do not attach to the sternum. The top 7 ribs usually attach to the sternum anteriorly, thus are influenced by sternal movement.
Physiologically normal breathing involves the sternum moving anteroposterior via sternoclavicular joint rotation. It is this movement that contributes to the pump-handle activity of the upper ribs.
The lower ribs laterally expand and open during inhalation, creating a bucket-handle movement. This motion occurs because the thoracic cavity expands anterolaterally by diaphragm and intercostal muscle activity.
But Life Isn’t All Love and Happiness
Breathing sometimes can occur pathologically. One example is paradoxical breathing. Here we see the diaphragm’s central tendon become fixed, leading the diaphragm to be eccentric upon inhalation and concentric upon exhalation. As a result, the lower ribs cranially elevate and intercostal spaces narrow. Accessory muscles begin assisting the breath, creating upper rib elevation.
Because the diaphragm does not assist postural stabilization as well, the paravertebral muscles kick into overdrive to keep us upright.
The sternum begins moving cranio-caudally, the acromioclavicular joint moves instead of the sternoclavicular joint. This change is one reason why we see shoulders elevate with accessory breathing. Hence, we can see why thoracic position is important for creating an ideal environment to breathe in.
These changes can correlate to pain states. In people with chronic low back pain, Pavel Kolar found increased flattening of the diaphragm’s lumbar portion. Another study demonstrated that decreased diaphragm activity during trunk stabilization posed a greater risk for developing low back pain.
The diaphragm can play a large influence on the viscera not only from an intra-abdominal pressure perspective but with digestion as well.
The diaphragm influences eating via the vagus nerve. In order for a bolus to reach the stomach, the diaphragm’s crural portion must relax. The reverse occurs when intragastric pressure must be attained, such as when the esophagus closes off from the stomach contents. So we can see that if diaphragm activity is not up to par, there is an increased risk of gastro-esophageal refux disease occurring.