Our soul moves, see that surgery is not done on that part of the body.

According to Buddhist sutra, the soul (la) is defined as the innermost, subtle essence of the five elements of space, air, fire, water and earth. 

The primary locus of the soul continually moves throughout the body and completes one full cycle each month in accordance with the cycle of the moon.  

In the Tibetan medical texts, which we also follow in Bhutan, it is advised not to bleed, damage, or conduct surgery in the area of the body in which the soul is located at any given time. Refer the image to check the location of soul at given lunar date.

The exact location of the soul differs slightly between texts.  The translation below is from the medical text, Menbum Karpo.

 

Further, if your health force is XX black, one should also avoid from carrying out operation on  the body.

While it sound bit bizarre, but that is how it is. Protection is always better then laughing at it and succumbs to the wound.