Physical Exam
Examination of the thyroid gland provides a simple means for the early detection of disease, since the thyroid gland itself is almost always the primary site of this dysfunction. Thyroid abnormalities customarily take the form of either a diffuse enlargement (goiter), nodule(s) and/or changes in gland consistency. Since thyroid examination is a relatively easy task, all physicians should become skilled at its performance.
The key to accurate thyroid examination primarily relies on visual inspection rather than palpation.
The physician should visually locate the laryngeal cartilages and the first three tracheal rings. The latter may require some palpatory confirmation. The two lobes of the thyroid gland are normally located laterally to the trachea, at the level of the second and third tracheal rings. Utilizing a proper level of oblique lighting, the patient should then be asked to swallow. The examiner should attempt to visualize the two oblong thyroid lobes as they rise and fall along with the trachea during deglutition. If significant enlargement is present, one or both lobes will usually be seen. Occasionally, a normal gland can also be visualized in patients with long thin necks, but this is uncommon. In patients with short or thick necks, on the other hand, even enlarged thyroid glands may not be seen because they are hidden by subcutaneous tissues. With diffuse hypertrophy, the gland is often asymmetrically enlarged with the right lobe characteristically being larger than the left. Additionally, enlargement of the thyroid isthmus (nominally located at the third distinct tracheal ring and usually not palpable) is often present in association with diffuse hyperplasia, and in the extreme, it may form a third thyroid mass which can be equal in size to the two thyroid lobes. This latter finding is often seen in patients with a history of long-standing nodular goiter.
Only after careful inspection of the neck and thyroid should the physician proceed with palpation. The normal thyroid gland is very soft, having the consistency of fatty tissue, and therefore is not easily palpable from other neck structures except with swallowing. Swallowing can be assisted by having the patient take multiple sips of water. If the thyroid gland can be palpated without swallowing, it most likely indicates the presence of underlying disease. In certain pathologic states the gland may have the consistency of a lymph node, as with chronic autoimmune thyroiditis (Hashimoto's thyroiditis), or may be very firm, as is typical of a thyroid cyst. Palpation of the gland may be performed by either a posterior or anterior approach as indicated by the ease and convenience to both the examiner and the patient. When the gland is located low in the neck or substernally, examination may be facilitated by having the patient lie supine with a fully extended neck.
For More Information
- American Thyroid Association
- Thyroid Foundation of Canada
- National Graves' Disease Foundation
- Gland Central
- American Association of Clinical Chemistry (Clinical Chemistry Journal)
- The Endocrine Society
- CLIANet (Clinical Laboratory Improvement Amendments)
- NCCLS (National Committee for Clinical Laboratory Standards)
