02/01/2026
๐จ ๐ง๐ต๐ฒ ๐๐ถ๐ฎ๐ฝ๐ต๐ฟ๐ฎ๐ด๐บ: ๐ ๐ผ๐ฟ๐ฒ ๐ง๐ต๐ฎ๐ป ๐ฎ ๐๐ฟ๐ฒ๐ฎ๐๐ต๐ถ๐ป๐ด ๐ ๐๐๐ฐ๐น๐ฒ
From an Equine osteopathic perspective, the diaphragm is one of the most influential structures in the horseโs entire body, yet itโs still commonly thought of as โjustโ a breathing muscle.
๐ ๐ฆ๐ด, ๐ช๐ต ๐ฑ๐ญ๐ข๐บ๐ด ๐ข ๐ค๐ฆ๐ฏ๐ต๐ณ๐ข๐ญ ๐ณ๐ฐ๐ญ๐ฆ ๐ช๐ฏ ๐ณ๐ฆ๐ด๐ฑ๐ช๐ณ๐ข๐ต๐ช๐ฐ๐ฏ.
But more accurately, the diaphragm is a pressure regulator, a mechanical integrator, and a meeting point between structure, organs and the nervous system.
๐ช๐ต๐ฎ๐ ๐๐ต๐ฒ ๐ฑ๐ถ๐ฎ๐ฝ๐ต๐ฟ๐ฎ๐ด๐บ ๐ฎ๐ฐ๐๐๐ฎ๐น๐น๐ ๐ถ๐:
The diaphragm is a large, dome-shaped musculotendinous structure separating the thoracic (chest) cavity from the abdominal cavity.
It is not a flat sheet > it is a dynamic, three-dimensional structure designed to move, adapt and transmit force.
๐๐ป๐ฎ๐๐ผ๐บ๐ถ๐ฐ๐ฎ๐น๐น๐, ๐๐ต๐ฒ ๐ฑ๐ถ๐ฎ๐ฝ๐ต๐ฟ๐ฎ๐ด๐บ ๐ฎ๐ป๐ฐ๐ต๐ผ๐ฟ๐ ๐ถ๐ป๐๐ผ ๐ธ๐ฒ๐ ๐๐๐ฟ๐๐ฐ๐๐๐ฟ๐ฎ๐น ๐ฟ๐ฒ๐ด๐ถ๐ผ๐ป๐:
โฆ๏ธThe Sternum (Sternal Fibres): The ventral part of the diaphragm attaches to the xiphoid process (the rear part of the breastbone).
โฆ๏ธThe costae (ribs)often listed around ribs 9โ18, depending on the source
โฆ๏ธThe lumbar spine (crural attachments)
At its centre lies the central tendon, a strong tendinous region that acts as a hub for pressure transmission and mechanical continuity.
From this centre, the diaphragm forms two domes, left and right, which attach caudally into the lumbar spine via the crura:
โก๏ธThe right dome and right crux are stronger and extend further caudally into the lumbar region
โก๏ธThe left dome and left crux are shorter and less robust
This asymmetry is normal, but it has important implications for spinal mechanics, visceral tension and movement patterns.
(These implications will be explored in later parts of this series.)
โผ๏ธ๐ช๐ต๐ฎ๐ ๐บ๐ฎ๐๐๐ฒ๐ฟ๐ ๐ต๐ฒ๐ฟ๐ฒ ๐ถ๐ ๐๐ต๐ถ๐:
The diaphragm is structurally integrated into the ribs, sternum and lumbar spine, it cannot move well if those structures cannot move well.
๐๐ฐ๐ธ ๐ช๐ต ๐ด๐ฉ๐ฐ๐ถ๐ญ๐ฅ ๐ฎ๐ฐ๐ท๐ฆ:
During the process of both inspiration and expiration, the diaphragm should move rhythmically:
Caudally and ventrally (backwards and downwards) on inspiration
Cranially (forwards towards the head) on expiration
When the diaphragm contracts, it flattens and moves caudally.
This caudalโventral movement creates expansion in three dimensions:
Vertical: the dome descends
Transverse: the ribs widen and elevate
Sagittal: the sternum lifts
๐๐ ๐ฎ ๐ฟ๐ฒ๐๐๐น๐:
Pressure within the chest cavity drops, drawing air into the lungs
The abdominal contents are gently compressed and then released
Pressure is redistributed rather than trapped
During expiration, the diaphragm returns cranially with a smaller amplitude, relying on rib mobility and abdominal compliance to regulate airflow and pressure efficiently.
Crucially, as the ribs move ventrally at the costovertebral joints, the spine is passively guided into extension, allowing the vertebral column to follow the respiratory motion while maintaining integrity of the spinal canal.
Straight away, we can see why rib mobility, sternum alignment and thoracolumbar freedom are so important for something as seemingly simple as breathing. Here we can think of why thoracic adjustments without rib n diaphragm & visceral assessment may not bring real long term alignment!
Why this matters beyond breathing
Because the diaphragm attaches to the ribs, sternum and lumbar spine, and blends into fascial continuities with the liver, stomach, spleen and kidneys, its movement affects far more than respiration.
When diaphragmatic motion is free and elastic:
โด๏ธThe ribs, spine and viscera move as a coordinated unit
โด๏ธBlood and lymphatic flow are supported
โด๏ธPressure is managed efficiently throughout the body
In faster gaits such as canter and gallop, this becomes even more relevant.
At that point, breathing and locomotion are mechanically linked โ๏ธ the diaphragm becomes the primary driver of respiration, working in rhythm with spinal motion and abdominal mass.
If it cannot move well, the horse must compensate elsewhere.
๐๐ผ๐ ๐ฟ๐ฒ๐๐๐ฟ๐ถ๐ฐ๐๐ถ๐ผ๐ป ๐ฐ๐ฎ๐ป ๐๐ต๐ผ๐ ๐๐ฝ:
When diaphragmatic movement is restricted; whether by rib stiffness, fascial tension, visceral load or neurological irritation, the effects are rarely local.
This is why diaphragm restriction may present as:
ยฐReduced performance or stamina
ยฐRib or thoracolumbar stiffness
ยฐApparent loss of core stability
ยฐHindquarter or โterrain-relatedโ issues
ยฐHorses that look barrel-shaped or bloated > then visibly change after treatment
Many owners are surprised when a horse looks physically slimmer or lighter post-treatment.
That isnโt weight loss, itโs pressure redistribution.
๐ง ๐ง๐ต๐ถ๐ ๐ถ๐ ๐ฃ๐ฎ๐ฟ๐ ๐ญ ๐ผ๐ณ ๐ฎ ๐๐ฒ๐ฒ๐ธ๐ฒ๐ป๐ฑ ๐๐ฒ๐ฟ๐ถ๐ฒ๐ ๐ฒ๐
๐ฝ๐น๐ผ๐ฟ๐ถ๐ป๐ด ๐๐ต๐ฒ ๐ฑ๐ถ๐ฎ๐ฝ๐ต๐ฟ๐ฎ๐ด๐บ ๐ณ๐ฟ๐ผ๐บ ๐บ๐ ๐๐ถ๐ฒ๐๐ฝ๐ผ๐ถ๐ป๐.
Over the coming parts, Iโll begin to unpack:
Its anatomical relationships in more depth
Why ribs and sternum matter so much
How pressure, posture and organs influence one another
And why diaphragm work is never just about breathing.
Some parts will be subscriber-only, where Iโll go deeper into clinical thinking, assessment priorities and real-world patterns I see repeatedly in practice.
๐ฉ For professionals: this topic alone forms multiple days of CPD content coming in March.. There is far more to this than can ever fit into a social media post.
๐ Part 2 next weekend: the anatomy and pressure story behind the diaphragm.
