Zone of Apposition
Definition
The area where the diaphragm is in direct contact with the inner surface of the lower rib cage. In a neutral rib cage position, this zone spans approximately ribs 7-10 and provides the mechanical advantage the diaphragm needs to descend effectively during inhalation. When the rib cage flares (externally rotates), the zone of apposition decreases, reducing diaphragmatic efficiency.
Clinical Significance
The zone of apposition is the single most important concept connecting breathing to posture. When the rib cage is stuck in an externally rotated (flared) position, the diaphragm loses its dome shape and cannot descend properly. This forces accessory breathing muscles (scalenes, sternocleidomastoid, upper traps) to compensate, creating chronic neck and shoulder tension. Rib cage repositioning targets the zone of apposition, which is why breathing is assessed even when the symptoms seem unrelated to it.
How AKMI Assesses This
AKMI evaluates the zone of apposition indirectly through infrasternal angle measurement, rib cage excursion testing, and breathing pattern observation. An infrasternal angle greater than 90 degrees suggests loss of zone of apposition. The assessment also checks for accessory muscle activation during resting breathing.
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A biomechanical assessment measures zone of apposition and its relationship to the rest of your structural chain. 18 tests, objective data, personalized programming.