Thyroid and Parathyroid Glands

Abstract

1. Pyramidal lobe: a remnant of descent of the thyroid that usually arises from the isthmus. Present in up to 40% of population. 2. Posterior suspensory ligament of the thyroid (ligament of Berry): a condensation of the thyroid fascia. It is well vascularized, deriving a branch of the inferior thyroid artery. 3. Internal branch of superior laryngeal nerve (SLN): supplies sensation to the lower pharynx, supraglottic larynx, and base of tongue. 4. The internal branch of SLN travels medially to the carotid system, entering the posterior aspect of the thyrohyoid membrane. 5. External branch of SLN: provides motor innervation to the cricothyroid muscle. 6. The SLN’s external branch diverges from the superior pole vascular pedicle 1 cm or more above the superior aspect of the thyroid superior pole. 7. Recurrent laryngeal nerve (RLN): provides motor innervation to the inferior constrictor and all intrinsic laryngeal muscles except the cricothyroid. 8. The right RLN ascends the neck, traveling from lateral to medial, crossing the inferior thyroid artery. 9. The left RLN ascends in a more paratracheal position, crossing the distal branches of the inferior thyroid artery. 10. Tubercle of Zuckerkandl: a pyramidal extension of the thyroid gland, present at the most posterior side of each lobe. It is a reliable landmark for the RLN in thyroid surgery.