“…The loosened rib cartilage may sublux superiorly with activities such as respiratory movements, certain movements of the thorax and upper extremities, or with external influences such as palpation by the examiner. The rib end may also sublux across the medial attachment site or another rib border, creating a sensation to the patient of a popping, clicking, snapping, grating or ‘giving way’ sensation simultaneously associated with a sudden, often severe, exacerbation in pain (3). Pain may then may fade away over the course of minutes to 1–2 h, or may persist as a lesser, dull pain punctuated by severe periodic exacerbations induced by subluxations.…”