<prompt> In emergency tracheostomy all structures are damaged except:Isthmus of thyroidInferior thyroid aeryThyroid imaInferior thyroid vein  <response>: Emergency tracheostomy can damage midline structures such as : thyroid isthmus, thyroid ima aery and inferior thyroid vein. Whereas, inferior thyroid aery lies laterally away from midline and so escapes injury. 