This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid, Subject name: Surgery
Isthmus of thyroid gland overlies the: 
Select and explain. 
A. 1st tracheal cailage, B. 1st and 2nd tracheal cailage, C. 2nd and 3rd and 4th tracheal cailage, D. 3rd and 4th tracheal cailage
C: 2nd and 3rd and 4th tracheal cailage
Answer: C: 2nd and 3rd and 4th tracheal cailage 
Explanation: THYROID GLAND Normal weight of thyroid gland: 20-25 gms Isthmus that is located just inferior to the cricoid cailage, usually anterior to 2nd and 3rd (mainly) 4th tracheal rings. A pyramidal lobe is present in about 50% of patients. Thyroid capsule is condensed into the posterior suspensory or Berry's ligament near the cricoid cailage & upper tracheal rings. External laryngeal nerve runs close to the superior thyroid aery and the recurrent laryngeal nerve runs close to the inferior thyroid aery.