title: Fossa posterior measurements: significance of sella to floor of 4th ventricle measurements (normal position of floor of 4th ventricle).
abstract: Two proportional methods are introduced to determine the normal position of the floor of the 4th ventricle expressed by two preventricular ratios: (see article); where ds = dorsum sellae, Ts = tuberculum sellae and Tw = Twining's line. T4 is the intersection between Tw and the floor of the 4th ventricle. The methods give information of the position of the 4th ventricle, the diameter of pons and the a-p diameter of the pituitary fossa.
mesh_terms: D000293:Adolescent; D000328:Adult; D002552:Cerebral Ventricles / Q000033:anatomy & histology*; D014695:Cerebral Ventriculography; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D011011:Pneumoencephalography