<prompt> Stereoanesthesia is due to lesion ofa Nucleus Gracilisb Nucleus cuneatusc Cerebral cortexd Spinothalamic tractabcbcacdbcd  <response>: AstereognosisStereoanaesthesia- Loss of ability to recognize size and shape of an object.Seen in- lesion of somatosensory cortex, lesion of tractus cuneatus, lesion of tractus gracilis.Somatosensory cortex lesion- proprioception and tactile sensations are lost while pain and temperature sensations are preserved. Tractus cuneatus- formed by fasciculus cuneatus spinal cord and nucleus cuneatus medulla. Pass through lateral portion of dorsal column. Carries sensations of dorsal column- proprioception and tactile sensations from upper part of the body.Tractus gracilis- formed by fasciculus gracilis spinal cord and nucleus gracilis medulla. Pass through medial portion of dorsal column. Carries sensations of dorsal column- proprioception and tactile sensations from lower part of the body. 