While the primary function of the hormones produced by the thyroid gland, which is regulation of body metabolism and functions such as temperature, blood pressure, heart rate and growth rate control, is common knowledge to many, the more elusive subject remains on the subject of ”where is the thyroid located?”. This is in part, because the education system tends to neglect the discussion, with all focus directed towards the function of the thyroid gland.
The thyroid is an endocrine gland that is found in all vertebrates and the hormones secreted play a vital role in different physiological processes. In humans, the thyroid gland, which is characteristically red-brown in color and surrounded by a dense network of blood vessels, consists of two lobes interconnected in the shape of a butterfly. It is located in the lower anterior neck region, just below the laryngeal prominence, which is also known as the Adam’s apple. The two thyroid lobes are joined together by a bridge-like structure called the isthmus, which lies along the length of the trachea.
From below the Adam’s apple, the glad extends to the fifth or sixth ring of the trachea, with the position varying significantly due to swallowing action. There is a third thyroid lobe in at least 40% of the human population called the pyramidal lobe or lalouette’s pyramid, which is essentially a vestigial remnant of the structure usually found during stages of embryonic development called the thyroglossal duct. This third lobe is in the shape of a cone and extends along the length of the trachea from the upper isthmus to the lingual or hyoid bone, which is located in the anterior mid-neck region.
In the tetrapod superclass, which includes all mammals, amphibians, reptiles and birds, the thyroid is commonly found in the neck region. The single-structured thyroid found in humans is common among many mammals, but the anatomy of the thyroid in most tetrapod species is such that there are two independent lobes with no linking bridge that lie in the neck region. In many different fish species, the thyroid gland is not separated into distinct lobes and lies just below the gills. Teleosts, members of the infraclass Teleostei represent a special grouping of fish for which thyroid development is found in other parts of the body. The common body parts that are associated with the thyroid gland tissue include the heart, eyes, kidneys and the spleen.
A healthy and functional thyroid gland is fundamental to overall health and wellbeing since it controls the body’s metabolism. An understanding of where is the thyroid located is therefore particularly important when performing an examination of the gland for medical reasons. While it may be invisible, the gland can be felt as a soft mass in the neck region. Qualified physicians use manual palpations to monitor thyroid texture and size, which helps in the detecting and examining any abnormal masses around the gland. Coupled with other appropriate examinations and tests, this provides the basis for correct diagnoses and any insightful prognosis. The examinations may help avert and treat common disorders associated with the gland.