Variations In The Course Of the Superior and Inferior Thyroid Arteries In Relation To the External & Recurrent Laryngeal Nerves

Introduction: A thorough knowledge of the thyroid anatomy and its associated anatomical variations is very important for the clinicians. The variations in the course of the vessels and nerves in the vicinity of the thyroid may prove to be a nightmare for surgeons. Therefore a detailed study on it equips the surgeon with vital information in the event of any such encounter. Aim & Objectives: To study the variations in the course of superior and inferior thyroid artery in relation to External laryngeal nerve (ELN) and Recurrent laryngeal nerve (RLN). Materials & Methods: The material for the present work (55 adult cadavers) was obtained from the bodies provided for dissection purpose from the Department of Anatomy, Andhra medical college Visakhapatnam, Rangaraya Medical College Kakinada, Shri Sathya Sai Medical College, Kancheepuram and also from the department of Forensic Medicine Andhra medical college Visakhapatnam. Observations: The right RLN was found anterior (40%) & posterior (55%) to the right Inferior thyroid artery and in between its branches in 5% of the specimens. On the right side, the artery was present in all specimens. The left RLN was found anterior (20%) and posterior (70%) to the left inferior thyroid artery and in between its branches in 7.5% of the specimens. In one body, the left inferior thyroid artery was absent. Thyroidea ima artery was not found in any of the 55 dissected specimens. Left superior thyroid artery, in all the 55 was seen to be arising from the front of the external carotid artery, just below the level of greater horn of hyoid bone, the external laryngeal nerve was located immediately posterior to it, at the apex of the lateral lobe of thyroid gland. On the right side, the External Laryngeal was found posterior (80%) & anterior (15%) to the Superior thyroid artery & in between its branches in 5%. Conclusion: The anatomy of thyroid gland and its neighboring structures highlighted in this study are of fundamental significance in the surgical treatment of various diseases and in curtailing operative errors.