Anatomy clinical correlates: Viscera of the neck

The neck houses a number of important anatomical structures and serves as the gateway between our head and body. These structures include major blood vessels and nerves, parts of the respiratory and digestive tract, as well as important endocrine glands such as the thyroid and parathyroid glands. However, the neck is very exposed and vulnerable to injury, and all of these important structures in the neck are susceptible to a variety of clinical conditions. So take a quick moment, stretch out your neck, and let's get started!

Let's begin with the thyroid gland. When there is abnormal growth of the thyroid gland, it is called a goiter. When the gland gets big enough, it can be seen as a bulge in the lower part of the neck, and may even extend deep to the sternum. Causes of a goiter include iodine deficiency, autoimmune disorders such as Hashimoto’s thyroiditis and Graves disease, thyroid cancer, or a thyroid cyst. 

The thyroid gland can enlarge anteriorly, posteriorly, inferiorly, laterally, or even substernally, but it won't enlarge superiorly because of the superior attachments of the overlying sternothyroid and sternohyoid muscles. 

If it enlarges, it has the potential to compress nearby structures such as the trachea, causing difficulty breathing; the esophagus, leading to difficulty swallowing; the recurrent laryngeal nerves, leading to hoarseness; as well as the jugular veins, leading to thrombosis and superior vena cava syndrome in rare cases.