Topographical anatomy of the anterior cervical approach for c2-3 level

To develop a clinically relevant anterior cervical approach (ACA) to the C2-3 level. Frequently encountered nerves [hypoglossal (HyN), internal (ISLN) and external superior laryngeal nerves (ESLN)] and vessels [lingual (LiA), superior laryngeal (SLA) and superior thyroid arteries (STA)] in the field of high ACA and the anatomic spatial markers [submandibular gland (SMG); sling for digastrics muscle (SDG); hyoid bone (HyB), and thyroid cartilage (ThC)] were evaluated using 18 fresh cadavers. The vertical distance of each structure at the carotid sheath and larynx and each disc for cervical level were measured from the suprasternal notch. The cervical levels of SDG, SMG and HyB were mostly C3 and that of ThC was C5. The vertical locations of HyN and LiA were not significantly different and the levels corresponded to C2. The levels for ISLN and ESLN were C3 at carotid and C4 and C5 at larynx sides, respectively. The vertical locations of ISLN and HyN were significantly different at carotid (p = 0.001) and larynx (p < 0.001) sides. The vertical locations and cervical levels of SLA and STA at carotid and larynx sides were not significantly different with those of ISLN and ESLN, respectively. The HyN traversed C2 with accompanying LiA. The ISLN passed C3 and C4 from carotid to larynx sides and accompanied SLA. The C2-3 level can be exposed through the space between the HyN and the ISLN by retracting the LiA superiorly, the SLA inferiorly, the HyB medially, and the carotid sheath laterally.