Posterior atlanto-occipital and atlanto-axial area: and its surgical interest

Classic anatomical studies describe two membranes - atlanto-occipital and atlanto-axial in the posterior aspect of the craniocervical region. During many surgical procedures in this area, however, we have not found such membranes. Objective: To clarify the anatomical aspects and structures taking part of the posterior atlanto-occipital and atlanto-axial area. Method: Analysis of histological cuts of three human fetuses and anatomical studies of 8 adult human cadavers. Results: In both atlanto-occipital and atlanto-axial areas, we have observed attachment between suboccipital deep muscles and the spinal cervical dura. However, anatomical description of such attachments could not be found in textbooks of anatomy. Conclusion: Our study shows the absence of the classical atlanto-occipital and atlanto-axial membranes; the occipito-C1 and C1-C2 posterior intervals are an open area, allowing aponeurotic attachment among cervical dura mater and posterior cervical muscles.