ABSTRACT
The thyroid gland develops in the embryo at the base of the tongue. It descends through the tissues of the anterior neck and finally comes to rest overlying the trachea and larynx. The thyroid tissue is very vascular and consequently trauma to the thyroid can result in impressive bleeding into the neck. Bleeding into thyroid cysts is relatively common; this will lead to a rapid enlargement, which is often painful due to stretching of the capsule of the gland. Usually during examination of a normal neck, the thyroid gland will be neither seen nor felt. Thyroid surgery is usually performed by general or ENT surgeons. Histological examination of thyroid tissue shows the gland to be composed largely of follicles and supporting cells. In cases of hypothyroidism, thyroxine replacements are required on a daily basis; after thyroidectomy, treatment is mandatory for life. Some types of thyroid tumour trap iodine, and this ability can be determined via an isotope scan.
