In total thyroidectomy, the parathyroid glands are at risk. The superior parathyroid gland develops from which pharyngeal pouch and is therefore more constant in position?

• A Third pharyngeal pouch — travels a longer distance and is more variable
• B Second pharyngeal pouch
• C Fifth pharyngeal pouch
• D Fourth pharyngeal pouch — travels a shorter distance and is more constant ✓

Explanation

The superior parathyroid gland develops from the 4th pharyngeal pouch and migrates only a short distance, making its final position constant (posterior aspect of mid-upper thyroid lobe). The inferior parathyroid gland develops from the 3rd pharyngeal pouch (same pouch as the thymus), migrates a longer distance, and is therefore more variable in position (may be in the mediastinum with an undescended thymus). This embryological fact explains why inferior parathyroids are harder to identify surgically.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.