opisthion การใช้

The "'opisthion "'is the midpoint on the posterior margin of the foramen magnum and is a cephalometric landmark.
By convention the cerebellar tonsil position is measured relative to the basion-opisthion line, using sagittal T1 MRI images or sagittal CT images.
The Powers ratio was formerly used, which was the tip of the basion to the spinolaminar line, divided by the distance from the tip of the opisthion to the midpoint of the posterior aspect of the anterior arch of C1.
The measurements and landmarks used in this program to compare an unknown cranium with the database consist of glabello-occipital length, nasio-occipital length, basion-palate breadth, bimaxillary breadth, zypomaxillary subtense, bifrontal breadth, nasio-frontal subtense, biorbital breadth, interorbital breadth, cheek height, frontal chord, nasion-bregma subtense ( frontal subtense ), parietal chord, bregma-lambda subtense ( parietal subtense ), occipital chord and lambda-opisthion subtense ( occipital subtense ).