The chart presented here is not associated with any question, event or native.
It has been cast solely to represent a planetary configuration with the purpose of demonstrating a traditional astrology technical point.

In a discussion forum, a fellow astrologer made the following statement:
“The Sun has power over Mars due to the Sun being in Mars’ sign.”
I have heard that type of statement before so I will state it simply:
That is the wrong way to read a dispositor.
A dispositor is the ruler of the sign any planet is found in. The dipositor “disposes of” whatever is in the sign it rules. The Sun is in Scorpio so Mars disposes of The Sun. So, it is Mars who has power over the Sun, not the other way around.
If someone visits your house he does not become the master of your house just by being there, does he? You remain your house’s owner and master (whether you are at home or not). Whoever is in your home is under your rule. Even if you went out to run an errand while someone came to visit you still own your house and therefore have the right to “dispose of” your house and whoever is in it.
In the chart above the Sun is visiting Mars’ home (Scorpio) while Mars is visiting Saturn’s home (Aquarius); Mars has not ceased being the ruler of Scorpio. And the Sun certainly has not become the ruler of Scorpio just because it is strolling in that sign or because Mars went out. Therefore Mars is still the ruler or “dispositor” and thus has power over whoever is in Scorpio.
That is the basic logic and theory.
Whether disposition is a relevant concept and/or Mars can or will exercise that power will depend on factors such as the question being asked, the context, essential and accidental dignity, and other receptions and aspects.
In medical matters, finding a person’s significator in the sign of L10, the significator of a treatment is a positive testimony (to be assessed along with any other positive and/or negative testimonies, such as the treatment itself), indicating that the treatment has power over the person’s health. The same is the case if the significator of the illness is in the sign of L10, indicating the treatment has power over the illness; for the logical reason explained above.