During total thyroidectomy for Graves' disease, the surgeon intentionally ligates the inferior thyroid artery medially (close to the gland) to preserve parathyroid vascularity. Which vascular anastomotic relationship makes this manoeuvre protective?

• A The superior thyroid artery provides the dominant supply to all four parathyroids
• B Ligating the inferior thyroid artery close to the gland preserves the 'end artery' branches to each parathyroid that arise proximally
• C The parathyroids are supplied exclusively by branches of the superior thyroid artery that anastomose with the inferior thyroid artery laterally
• D The inferior thyroid artery supplies both upper and lower parathyroids through a capsular arcade, so central ligation preserves collateral flow ✓

Explanation

The inferior thyroid artery typically supplies both the superior and inferior parathyroids via a capsular arcade. Ligating the inferior thyroid artery far lateral to the gland (at its main trunk) risks avulsing all branches to the parathyroids; ligating it medially close to the thyroid capsule preserves the more proximal vascular pedicle to the parathyroids while sacrificing only terminal thyroid branches. This is standard teaching for protecting parathyroid viability.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.