The structure damaged in High Tracheostomy ?
Ans. is'c' i.e., First tracheal ring(Ref: Dhingra dle p' 317)High tracheostomy: Performed above the level of thyroid isthmus which lies against II, III and IV tracheal rings:Indicated in carcinoma larynx when laryngectomy is anticipated.Drawback : tracheostomy at this point violates the 1st ring of trachea and causes perichondritis of the cricoid cailage and subglottic stenosis, so it is better avoided.
Thyroid isthmus
Aoic knuckle
First tracheal ring
Recurrent laryngeal nerve