History of Cervical Spine Localization: Surface Landmarks

Introduction: Interest in the relational anatomy of the anterior neck among spine surgeons grew following the popularization of the anterior cervical discectomy and fusion (ACDF) in the 1950’s. We aimed to investigate the origins of commonly quoted anatomic relationships between palpable surface anatomy and osseus cervical spine anatomy.

Methods: A narrative review was performed. Pubmed and EMBASE databases were searched for articles relevant to the origin of surface landmarks for localization to the cervical spine. Original manuscripts of landmark studies on approaches to the ventral/anterior cervical spine and contemporary textbooks were reviewed for language on surface localization. References of all texts were searched for additional relevant material.

Results: We identified five surface landmarks consistently described in the literature: the angle of the mandible (C2-C3 interspace), Hyoid bone (C3 body), Thyroid cartilage (C4-C5 interspace), Cricoid cartilage (C6 body), and Carotid/Chassaignac tubercle (C6 body). Through review of the origin of these relationships we observed some common themes. First, the mid 19th century saw an explosion of interest in relational anatomy for deep seated structures. This was likely driven by the widespread adoption of general anesthesia, facilitating access of these structures to clinicians. Second, even at the time of their description, there has been debate over the reliability and validity of many of these surface approximations. Finally, with the modern availability of fluoroscopy and current medical-legal environment, the application of these landmarks in modern practice has been supplanted. However, they still serve as important concepts to reinforce surgical relational anatomy for trainees and clinicians.

Conclusion : Investigation around the historical context and basis of five surface landmarks for cervical spine localization highlights advancements and trends, not only in spine surgery but, in surgical and medical practice over the 19th and 20th century.