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Surgical Anatomy of the Thyroid
Published in Madan Laxman Kapre, Thyroid Surgery, 2020
Ashutosh Mangalgiri, Deven Mahore
The straps are innervated by a looped structure known as ansa cervicalis, embedded in the anterior wall of the carotid sheath. Ansa cervicalis has (1) anterior root, (2) posterior root, (3) loop of ansa (Figures 2.5 and 2.6).
Head and neck
Published in Tor Wo Chiu, Stone’s Plastic Surgery Facts, 2018
Nerves X within the carotid sheath and superior laryngeal branch.Lingual branch of V3 (one of the three sensory branches from the posterior division).XI (at the apex of the triangle).XII.Ansa cervicalis.
Head and Neck
Published in Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno, Understanding Human Anatomy and Pathology, 2018
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno
The hypoglossal nerve is easy to identify because it runs posteroanteriorly first, as one of the four major structures passing superficial to the hyoglossus muscle (see Box 3.10), and then deep to the mylohyoid muscle (Plate 3.41). The superior root of the ansa cervicalis travels with the hypoglossal nerve and is mainly composed of fibers from C1, whereas the inferior root of the ansa cervicalis is mainly composed of fibers of C2 and C3, and passes around the carotid sheath to join the superior root, thence the name “ansa” (handle).
Endotracheal Tube Electrode Neuromonitoring for Placement of Vagal Nerve Stimulation for Epilepsy: Intraoperative Stimulation Thresholds
Published in The Neurodiagnostic Journal, 2022
Gennadiy A. Katsevman, Darnell T. Josiah, Joseph E. LaNeve, Sanjay Bhatia
The ansa cervicalis is frequently located during surgeries in the anterior triangle of the neck and may be confused with the vagus nerve. The “ansa,” which in Latin refers to “handle of a cup,” refers to the superior root (descendens hypoglossi derived from the first cervical nerve, C1), the inferior root (descendens cervicalis derived from the ventral rami of C2 and C3), and the loop of their arrangement (Banneheka 2008b). The inferior root of the ansa may lie medial to the internal jugular vein (IJV) in 15% of cases and there can be communication between the ansa cervicalis and the vagus nerve, with the superior root of the ansa and the vagus running in a single connective tissue sheath; this may result in neck muscle contractions during the implantation of a vagal nerve stimulator (Banneheka 2008a; Gopalakrishnan et al. 2015). One study demonstrated that the ansa cervicalis of lateral type was observed in 34% of cases (i.e., when the inferior root runs anterior to the IJV to form the ansa on the anterior surface of the carotid sheath), medial type in 63% of cases (i.e., inferior root posterior to the IJV to form the ansa deep), and mixed type in 3% of cases (Banneheka 2008b). The vagus nerve, on the other hand, exits via the jugular foramen and runs down vertically in the carotid sheath between the internal carotid artery and the IJV and then between the IJV and common carotid artery (CCA) more distally. This, too, varies: a study determined that the vagus nerve was anterior to the CCA and IJV in 4% of cases, posterior to the CCA in 15% of cases, posterior to the IJV in 8% of cases, and posterior to but between the CCA and IJV in 73% of case (Dionigi et al. 2010). Given these variations, it is possible that the inferior root of the ansa cervicalis may be incorrectly identified as the cervical vagus trunk during the implantation of a VNS.