CASE 58
WHAT ARE THE GROSS ANATOMICAL CHARACTERISTICS OF THE PARATHYROID GLANDS?
The parathyroid glands have the following gross anatomical characteristics:
• Although the number of parathyroid glands is variable, there are normally four: a pair of superior and a pair of inferior glands (Fig. 7-28).
• Superior parathyroid glands are embedded in fat posterior to the superior lobe of the thyroid gland.
• Inferior parathyroid glands are more variable in location. They may be located in the fascial thyroid sheath caudal to the inferior thyroid artery; external to the thyroid sheath cranial to the inferior thyroid artery; and in the inferior pole of the thyroid gland. These locations are of surgical significance. Tumors of the parathyroid glands located in the fascial thyroid sheath may migrate along the inferior thyroid veins into the superior mediastinum by passing anterior to the trachea. If the inferior parathyroid glands are located outside the sheath, a tumor may extend into the posterior mediastinum by descending posteroinferiorly to the esophagus.
FIGURE 7-28 Relationship of parathyroid glands to the inferior thyroid artery and the recurrent laryngeal nerve.
(Towsend C et al.: Sabiston Textbook of Surgery, 17e. WB Saunders, 2004. Fig. 35-9. From Yim JH, Doherty GM: Operative strategies in primary hyperparathyroidism. In doherty GM, Skogseld B (eds): Surgical Endocrinology. Philadelphia, Lippincott Williams & Wilkins, 2001, p. 167.)
WHAT IS THE ARTERIAL SUPPLY TO THE PARATHYROID GLANDS?
The rich arterial supply to the parathyroid glands is from the inferior thyroid artery or the anastomosis between the superior and inferior thyroid arteries (Fig. 7-28).
WHAT IS THE LYMPHATIC DRAINAGE OF THE PARATHYROID GLANDS?
Lymphatic vessels drain into the deep cervical and paratracheal lymph nodes.
