Medical Information Regarding the Vacuum Bell

Bending moments: The vacuum pulls the breastbone from its caved-in position into a raised position. The cartilaginous rib ends and costal arches, which are attached to the breastbone, are also pulled into a raised position. Simultaneously and with equivalent force, the rims of the vacuum bell press on the human body. The stress of these concurrent forces produces bending moments, primarily in the breastbone area and at the funnel edges. The bending moments at the funnel edges are counterbalanced by the anchorage of the ribs to the spinal column (backbone). These bending moments transform the cartilaginous rib-endings and costal arches, and the two moveable breastbone-hinges. Correction of the funnel is brought about primarily by their transformation.

Lifting of the funnel involves a 3-part process effecting the bones, cartilages and ligaments of the
ribcage: an initial, reversible (elastic) deformation; a gradual, permanent transformation;
and micro-ruptures, most likely occurring at the beginning of the treatment. Until these ruptures heal, the patient’s ribcage will experience a slight temporary loss of firmness.

The funnel's return to its concave position upon removal of the vacuum bell might be explained via the analogy of a competition between the ribcage's firmness and the pull of muscles, including the diaphragm. Optimal responses to therapy appear to result from lifting the funnel slowly and continuously in such a way that the teporary losses of firmness in the ribcage are kept to a minimum.

Gradual progress is best: It should take some time (even 2 to 4 weeks) for the chest to be lifted to the degree that the funnel comes into contact with the viewing glass. The inward-pulling muscles, such as the diaphragm, become stretched by lifting the chest wall. As a result of the complete duration of treatment, these muscles grow accustomed to their new position and
to pulling the funnel less forcefully. In many cases, this growing process takes longer than any other part of the treatment.