Sarvangasana has a profound and characteristic influence on the thyroid gland. Because of the importance of this small gland, it is worthwhile giving a brief description of its anatomy, functions and relationship with various types of disease.
The thyroid gland is an important part of the endocrinal system. It is a small butterfly-shaped organ located just below the voice-box (larynx) in the front part of the neck. It has two lobes, each of which is about 4 cms long and weighing 10 grams. These lie on either side of the windpipe and are joined by a narrow band or bridge of tissue which crosses in front of the windpipe.
The thyroid gland produces thyroxin (as well as tri-iodothyronin), a powerful hormone that affects practically every cell in the body. Its main function is to regulate the rate at which food and oxygen are utilized by the various cells of the body. This is known as metabolism.
This gland has a profound influence on physical, emotional and mental development. In a healthy person, the correct amount of thyroxin hormone is produced and secreted to meet his or her particular needs. This is clearly shown by abundant energy and the ability to work and play without undue fatigue.
If the thyroid is out of balance then it can secrete too little thyroxin hormone. This condition is known as hypothyroidism. It tends to make the individual sluggish and sleepy. All the bodily functions slowdown. The intellectual faculties are dulled The individual tends to become fat, constipated, apathetic, and indolent. If this malfunction occurs in children, it can lead to dwarfism, deformity and a generally retarded mental development.
On the other hand, a malfunctioning thyroid can also produce too much thyroxin. This is called hyperthyroidism. This leads to a speeding up of all the bodily functions. A person with this ailment tends to be continually overactive, both physically and mentally, and is unable to relax. There is a general loss of weight, diarrhoea, increased blood circulation and respiration, extreme nervousness and excitability and often psychotic symptoms. If this malfunction occurs in children, then it can lead to excessive physical growth, so that the child becomes abnormally large. This has led to persons growing to heights of two and a half meters.
We have indicated only the basic symptoms of a faulty thyroid gland. There are a multitude of specific diseases that can occur, too numerous to mention in this brief summary. The important thing that we have tried to indicate is that disease can result if the thyroid produces either too much or too little thyroxin. For perfect health there has to be perfect balance.