Anatomical considerations of the superior thyroid artery: its origins, variations, and position relative to the hyoid bone and thyroid cartilage

Abstract

The aim of this study was to provide accurate anatomical descriptions of the overall anatomy of the superior thyroid artery (STA), its relationship to other structures, and its driving patterns. Detailed dissection was performed on thirty specimens of adult's cadaveric neck specimens and each dissected specimen was carefully measured the following patterns and distances using digital and ruler. The superior thyroid, lingual, and facial arteries arise independently from the external carotid artery (ECA), but can also arise together, as the thyrolingual or linguofacial trunk. We observed that 83.3% of STAs arose independently from the major artery, while 16.7% of the cases arose from thyrolingual or linguofacial trunk. We also measured the distance of STA from its major artery. The origin of the STA from the ECA was 0.9±0.4 mm below the hyoid bone. The STA was 4.4±0.5 mm distal to the midline at the level of the laryngeal prominence and 3.1±0.6 mm distal to the midline at the level of the inferior border of thyroid cartilage. The distance between STA and the midline was similar at the level of the hyoid bone and the thyroid cartilage. Also, when the STA is near the inferior border of the thyroid cartilage, it travels at a steep angle to the midline. This latter point may be particularly important in thyroidectomies. We hope that anatomical information provided here will enhance the success of, and minimize complications in, surgeries that involve STA.

A cadaveric study on variations in branching pattern of external carotid artery

“…Pseudoaneurysms occurring consequent to blunt carotid injury commonly affect branches of the ECA than the main ECA itself [4]. The clinical significance of the ECA and its branches is further reinforced by their application in a wide range of radiological and surgical procedures such as intra-arterial infusion chemotherapy [56], carotid stenting and endarterectomy [78] as well as various head and neck surgeries [91011]. A comprehensive understanding of the normal as well as variant anatomy of the ECA is hence essential for the discerning radiologist as well as the judicious surgeon for successful completion of procedures and avoidance of vascular complications in the head and neck region.…”

Origin of superior thyroid artery: under the surgeon’s knife

“…1 , 2 Conflicting reports have been published regarding the origins of the STA and SLA, such as the former arising from the common carotid artery (CCA) (1.5-47% of cases) or at the point of bifurcation of the common carotid artery (CCB) (21-49% of cases), and the latter arising from the ECA. 3 - 8 Anatomical variations of the STA are important during surgical and radiological intervention in the neck. Surgical procedures such as radical neck dissection, thyroidectomy, reconstruction of an aneurysm, cricothyroidotomy, carotid endarterectomy, cancer therapies, interventional radiology and plastic surgery all involve the STA.…”

Anomalous Origin of the Superior Thyroid Artery from the Internal Carotid Artery

“…Studying the variation of the STA is imperative as it has significant clinical implications for head and neck surgical procedures. STA is primarily the arterial supply for the thyroid gland, the upper larynx tissues, the skin, and neck muscles [3]. Damage to the artery can subsequently compromise these structures.…”

“…Furthermore, the external branch of the superior laryngeal nerve (EBSLN) is vulnerable to damage during surgical procedures as it runs medial to the STA and innervates the thyroid gland [1]. The STA is also a vital vessel for procedures such as emergency cricothyroidotomy, thyroidectomy, carotid endarterectomy, reconstructive surgery, diagnostics, and treatments of head and neck cancers such as radical neck dissections, and catheterization to deliver cancer therapeutics; therefore, there is significant clinical importance in studying the aberrations of the origins of the STA [3].…”