An axial CT of the neck shows a band of soft tissue density connecting the two lobes of the thyroid gland across the front of the trachea. At what level relative to the tracheal rings is the isthmus of the thyroid gland located?

• A Over the cricoid cartilage
• B From the fifth to the seventh tracheal rings
• C From the second to the fourth tracheal rings ✓
• D At the level of the sixth cervical vertebra only

Explanation

The thyroid isthmus crosses the trachea over the second to fourth tracheal rings, which is why a tracheostomy is performed below the fourth ring to avoid it. The cricoid cartilage lies above the isthmus at the B6 level, and the pyramidal lobe, when present, ascends from the isthmus toward the hyoid, not downward onto the lower rings.

Reference: Snell's Clinical Anatomy by Regions, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.