Cadaveric exploration of Ansa Cervicalis: A Sri Lankan Study

Introduction: The ansa cervicalis (AC) is a nerve loop which is arising from the cervical plexus (C1–C3). As it exhibits numerous anatomical variations and as Sri Lankan studies on the area are very minimal, this study aimed to investigate the variations of AC in relation to its location which can have significant clinical implications especially during neck surgeries.
Methods: Twelve bilaterally dissected cadavers were observed to explore the variation in location and symmetry of the AC by comparing both left and right sides in relation to internal jugular vein (IJV) and central tendon of the omohyoid muscle (CT-OM). In relation to the IJV, it is classified as lateral type and medial type. In relation to CT-OM, loop was observed as superior, inferior, or at the same level.  
Results: Twenty-one intact ACs were observed in eight male and four female cadavers bilaterally. There were 38% medial type and 62% lateral type ACs. In the nine bilaterally available cadavers, six (66.6%) were symmetrical in relation to IJV position and 3 (33.3%) were symmetrical in both parameters. Out of the 21 ACs, 15 (71.4%) were superior to CT-OM while four were (19%) at the same level and two (9.5%) were inferior to it.  
Conclusion: Our findings highlight the diverse anatomical variations in the location of the AC.  Knowledge of these variations is essential for surgical procedures and other interventions in the neck region to avoid injury and complications.