<prompt> Pancoasts syndrome is due to:-C4-5 invasionC8-T1 invasionLower trunk involvementC5-6 invasion  <response>: PANCOAST TUMOR SUPERIOR SULCUS TUMOR Pancoasts or superior sulcus tumor syndrome results for local extension of a tumor growing in the apex of the lung with involvement of eighth cervical and 1st and 2nd thoracic nerves, with shoulder pain characteristically radiates in the ulnar Often Horners syndrome and Pancoasts syndrome co-exist 