There is not a direct link, anatomically speaking, between the mediastinum and the kidney/adrenals, as they are in different body cavities – the mediastinum being above the diaphragm, the kidney/adrenals below. However, the human body is an intricate, interconnected system in ways that modern medical anatomy does not fully understand. Certainly there is always communication occurring within the entire system.

So, if you are working with your mediastinum and opening up into greater ease and flow, this could influence the entire survival physiology to lessen, and sympathetic activation could lessen in general, which could then result in the adrenals calming down, and the kidneys softening and dropping. Or, the opposite could happen. A person could uncover some piece of charge, some activation or traumatic memory the body was holding in the area of the heart, and this could spike the sympathetic system, causing the adrenals to become more active and the kidneys to tighten.