The thyroid gland is located in the lower neck, above the breastbone on either side of the windpipe. Its function is to provide the body with thyroid hormones, chemicals that are essential for the normal function of each cell organ in the body.
Thyroid pathology is very common. One in five people will develop a thyroid lump which needs medical attention. More than 20 million people in the US have an overactive or underactive thyroid, but half of them do not even know they have the disease. Even among those who know they have a thyroid condition, many are taking either too much or too little medication.
Thyroid problems manifest themselves as abnormalities of function or structure.
Structure abnormalities consist of goiter (an enlarged thyroid gland), and nodules or lumps. To rule out cancer, a thyroid fine needle aspiration is required (biopsy).
Function abnormalities comprise an overactive or an underactive thyroid. Both cause a variety of symptoms involving virtually every organ of the body, hence the difficulty in diagnosing the thyroid condition.
Thyroidology, the science of the thyroid, has undergone rapid development in the last years. For example, subclinical over- and underactive thyroid has been recently associated with bone loss, high cholesterol, heart problems, etc. Previously normal TSH levels are now under scrutiny.