Abstract
Background: The ansa cervicalis, a loop of nerves arising from the cervical plexus, plays a crucial role in innervating the infrahyoid muscles. Although typically formed by fibres from the C1–C3 spinal nerves, numerous studies have reported variations in its formation, particularly in the contribution to its superior and inferior roots The present study aimed to examine the anatomical variations in the formation of the ansa cervicalis, with special emphasis on the roots and their contributing spinal nerve fibres. Materials and Methods: The study was conducted on cadaveric specimens to observe the origin, formation, and variations of the ansa cervicalis. Particular attention was given to the contributions of cervical spinal nerves and any anomalous connections. Results: The majority of specimens demonstrated the classical formation of the ansa cervicalis from C1–C3 spinal nerve fibres. The inferior root was predominantly formed by contributions from C2 and C3. However, variations were noted, including a case where the inferior root arose solely from the C2 ventral ramus. Additionally, a rare variation was observed in which fibres from the vagus nerve contributed to the formation of the ansa cervicalis, specifically to the inferior root.Conclusion: The study confirms that while the typical pattern of ansa cervicalis formation is most common, significant anatomical variations exist. The identification of rare anomalies, such as vagal contribution, emphasizes the importance of detailed anatomical knowledge for clinicians and surgeons performing procedures in the cervical region.