Foramen transversariumAnterior tuberclePosterior tubercleArchSuperior articular facetBodyTransverse processSpinous processDensAnterior archArticular facetfor densLateral massSuperior articular surface (for occipital condyle)Posterior archBodyAtlas (CI)Axis (CII)Articular facetfor densABCDForamenmagnumOccipital condyleOccipital boneApical ligamentof densSuperior longitudinal bandof cruciform ligamentInferior longitudinal bandof cruciform ligamentTransverseligament of atlasAlar ligamentsETectorial membrane (upper partof posterior longitudinal ligament)Posteriorlongitudinalligament