23rd May 2025

Anatomy

The thyroid gland consists of a midline isthmus horizontally (below the cricoid cartilage) and two lateral lobes extending upwards over the lower half of the thyroid cartilage . The gland lies deep to the strap muscles, enclosed in the pretracheal fascia, which anchors it to the trachea and means the thyroid moves upwards on swallowing.

Anatomical relations

• Anteriorly: infrahyoid muscles
• Laterally: carotid sheath, comprising of the common carotid artery, internal jugular vein, and vagus nerve

Medially: larynx, pharynx, trachea, and oesophagus, and the external and recurrent laryngeal nerves (the left and right recurrent laryngeal nerves are in close proximity to the thyroid gland, and may be damaged by compression (e.g. by a nearby mass) or during thyroidectomy)