In Thai traditional medicine and spiritual practices, there is a concept known as "Sen" or "energy lines." These energy lines are similar to the meridians in traditional Chinese medicine and are believed to be channels through which life energy, or "lom," flows. The manipulation of these energy lines is a key component of traditional Thai massage and other Thai healing practices.

The primary energy lines in Thai traditional medicine are often compared to the pathways of the circulatory system. There are ten main Sen lines, with some variations in different schools of Thai massage.