<prompt> Pathognomic feature of hyperparathyroidism:Pathognomic feature of hyperparathyroidism:Loss of Lamina duraBrowns tumorSub periosteal resoption of phalynges  <response>: D i.e. Subperiosteal resorption of bone phalynges Very interestingQ friends as all the options are the features of hyperparathyroidism but they are asking about the hallmark or characteristic feature which is ? Subperiosteal Erosion of bone, paicularly radial aspect of middle phalynx of middle index finger.Q 