New data on landmark anatomy of the human superior thyroid artery

BACKGROUND: The description of anatomy of the thyroid vasculature is widely used in both traditional medical literature and modern research. However, authors note variability in locating the superior thyroid artery orifice relative to the common carotid artery bifurcation. However, there is no standard approach to determining the linear dimensions of the common carotid bifurcation zone. In this context, it is important for both morphologists and clinicians to determine the position of the superior thyroid artery orifice in relation to various anatomical landmarks. AIM: The aim of the study was to identify variations in the location of the superior thyroid artery orifice relative to the common carotid artery bifurcation, the superior edge of the thyroid cartilage, and the superior edge of the thyroid lobe as landmarks. MATERIALS AND METHODS: The study used 36 neck organ complexes obtained at autopsy from individuals without apparent thyroid disease using an original technique developed by the authors. The organ complexes were dissected, the arterial pool was injected with a colored gelatin-based compound, and the specimens were fixed. Photographs of the specimens were analyzed using a superimposed coordinate grid with a step size of 5 mm. RESULTS: Most commonly, the upper edge of the common carotid artery bifurcation was found at the level of the upper edge of the thyroid cartilage on the right side and below it on the left side. It was also located above the upper edge of the corresponding thyroid lobe bilaterally. The superior thyroid artery orifice was most commonly located in the area of the common carotid artery bifurcation bilaterally. A moderate direct correlation was found on the right side between the location of the superior thyroid artery orifice and the upper edge of the bifurcation relative to the upper edge of the thyroid cartilage (Rs = 0.402, p 0.05). There was also a direct strong relationship between the location of the superior thyroid artery orifice relative to the upper edge of the thyroid lobe and the length of the artery on the right side (Rs = 0.826, p 0.05). CONCLUSIONS: The study confirms the literature data regarding the variability of the superior thyroid artery location. The data obtained suggest that it is useful to use landmarks that can be easily determined during surgery to identify the location of the superior thyroid artery orifice.