Clinically relevant variations of the superior thyroid artery: an anatomic guide for surgical neck dissection.

The superior thyroid artery (STA) is the dominant arterial supply of the thyroid gland, upper larynx and the neck region. The knowledge of variations in possible patterns of origin, courses, and branching pattern of the STA is also important for surgical procedures in the neck region, such as emergency cricothyroidotomy, radical neck dissection, catheterization, reconstruction of aneurysm and carotid endarterectomy. The surgical anatomy of the STA was studied in 20 adult Anatolian preserved cadavers between the age of 40 and 70 years. The outer diameter of the STA origin was observed to be 3.53 +/- 1.17 mm. The location of the origin of the STA according to the carotid bifurcation was evaluated as above (25%), below (35%) and at the same level (40%). The distribution patterns of the STA were classified into six types depending on the branching pattern. The outer diameter of the infrahyoid branch, superior laryngeal artery, sternocleidomastoid artery and cricothyroid branch at their origins were observed to be 1.13 +/- 0.14, 1.42 +/- 0.47, 1.54 +/- 0.96 and 1.30 +/- 0.41 mm, respectively. Typical and variant glandular branching patterns were observed in 85 and 15% of the specimens, respectively. The outer diameters of anterior, anteromedial, anterolateral and posterior glandular branches were measured as 2.05 +/- 0.46, 1.41 +/- 0.43, 1.51 +/- 0.41 and 1.73 +/- 0.53 mm, respectively. It is necessary to understand the surgical anatomy of the STA to carry out successful radical neck dissection and to minimize postoperative complications in a bloodless surgical field.