This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Operative Surgery, Subject name: ENT
Mid tracheostomy is done over? 
Select and explain. 
A. 1st and 2nd tracheal rings, B. 3rd and 4th tracheal rings, C. 5th and 6th tracheal rings, D. 7th and 8th tracheal rings
B: 3rd and 4th tracheal rings
Answer: B: 3rd and 4th tracheal rings 
Explanation: ANSWER: (B) 3rd and 4th tracheal ringsREF: Dhingra 4th edition page 292Out of the options provided, option (B) appears to be more correctA mid tracheostomy is the preferred one and is done through the II or III rings and w'ould entail division of the thyroid isthmus (isthmus lies against II, III and IV tracheal rings) or its retraction upwards or downwards to expose this part of trachea.High tracheostomyAbove isthmus , violates the first ringCauses perichondritis and subglottic stenosis and only indication is carcinoma larynxMid tracheostomyOver the isthmus, 2ni and 3rd ringPreferred oneLow tracheostomyBelow isthmusRisk of damage to vessels and tube impinges upon suprasternal notch