Anatomical Variation in the Origin of Superior Thyroid Artery and It’s Relation with External Laryngeal Nerve

Background & aim: To identify the variations in site of origin and level of the origin of the superior thyroid artery and its relation with external laryngeal nerve. Material & Method: A study was undertaken on 33 donated cadavers and through dissection was performed in neck region and both sides of superior thyroid artery were considered. Results: in present study superior thyroid artery arise from external carotid artery in 66.67% cases, from carotid bifurcation in 31.81% cases and from common carotid artery in 1.51% cases. While in 86.36 % cases level of the origin was above the thyroid cartilage and in 13.64% cases level of the origin was at the same level of thyroid cartilage. The external laryngeal nerve crossed the superior thyroid artery within 1cm above the upper pole of the thyroid gland in 27.27% of cases and more than 1 cm in 72.73% of cases. Conclusion: The information will be useful as reference for surgical procedures such as total bilateral lobectomy, total unilateral with partial contralateral lobectomy and partial or subtotal lobectomy & others like catheterization, reconstruction of aneurysm, carotid endarterectomy and intervention radiology which is helpful to prevent complications such as bleeding or damage to laryngeal nerves.