The Cervical Ligamentum Flavum and Cervicodural Ligaments

STUDY DESIGN: Anatomic and histologic study of human cadaveric specimens. OBJECTIVE: To clarify the detailed anatomy of the cervical ligamentum flavum (LF), evaluate its presence at the craniocervical junction, and describe novel cervicodural ligaments with potential clinical implications. SUMMARY OF BACKGROUND DATA: The cervical ligamentum flavum is clinically important yet remains anatomically controversial, particularly regarding its presence and morphology at C1. MATERIALS AND METHODS: Twelve adult cadaveric necks were examined (six gross dissections, six histologic analyses). Specimens were sectioned coronally, sagittally, and axially. The Masson trichrome staining was used to identify ligamentous structures and their relationships with adjacent tissues. RESULTS: A distinct LF was consistently present between C2 and C7 vertebrae, attaching to adjacent laminae, blending laterally with the capsular ligament, and posteriorly with the interspinous ligament. No LF was identified at C0-C1. Instead, fibrous connections extended from the posterior arch of C1 and the lamina of C2 to the dura, forming previously undescribed atlantodural and axiodural ligaments. These cervicodural ligaments created a thickened dural region at C1-C2 and contained muscle fibers corresponding to the myodural bridge. A midline gap was observed between the right and left LF, traversed by vascular structures supplying the posterior cervical elements. CONCLUSIONS: The cervical LF is absent at C0-C1 ( i.e., posterior atlanto-occipital membrane), where novel cervicodural ligaments connect C1-C2 to the dura. These findings refine the surgical anatomy of the craniocervical junction and may provide an anatomic basis for cervicogenic headache.