<prompt> All of the follow ing lie between the 1st rib and the apex of the lung, except -Thoracic ductSuperior intercostal arteryFirst posterior intercostal veinSympathetic trunk  <response>: Ans. is a i.e.. Thoracic ductRelationship of lung apexIn front AnteriorSubclavian artery.Origini of internal thoracic artery from the 1st part of subclavian artery.Scalenus anterior muscle.Subclavian vein.Behind Posterioro A pex is in contact with neck of the 1st rib, and the following structures intervene between them from medial to lateral :-Sympathetic trunkFirst posterior intercostal veinSuperior intercostal arteryAscending branch of the ventral ramus of the lst thoracic nerve. It joins the 8th cervical nerve to form the lower trunk of the brachial plexus.LaterallyScalenus medius muscleLower trunk of brachial plexusMediallyRight lung from before backwardsRight bronchoceptalic vein accompanied by right phrenic nerve pericardio-phrenic vesselsBrachio-cephalic trunkTrachea acompanied by right vagusLeft lung from before backwardsa Left bronchcephalic veinb Left subclavian arteryc left edge of esophagusd Thoracic duct 