<prompt> Clicking noise in pneumomediastinum is known asHamman signTrail signKussmaul signnone  <response>: In pneumomediastinum,physical examination reveals subcutaneous emphysema in the suprasternal notch and Hammans sign,which is a crunching or clicking noise synchronous with the heabeat and is best heard in the left lateral decubitus position.Kussmauls sign is defined by either a rise or a lack of fall of the JVP with inspiration and is classically associated with constrictive pericarditis,restrictive cardiomyopathy,massive pulmonary embolism,right ventricular infarction,and advanced left ventricular systolic hea failure.Trail sign is the prominence of Sternocleidomastoid muscle on the side of tracheal detion. Ref:Harrisons medicine-18th edition,page no:2182,1823 