Inferior Thyroid Artery

Origin

• From Thyrocervical Trunk

Course

• Arches upwards and medially behind the Carotid Sheath
• Loops downwards to lower pole
• Divides outside Pretracheal Fascia into branches that pierce the fascia separately to reach the lower part of the gland
• Recurrent Laryngeal Nerve has variable relationship with artery
  • BUT always lies behind the Pretracheal Fascia
  • 85% - posterior and intertwined between branches
  • 15% - anterior (more common on the right)
  • To safeguard the nerve, ligate the Inferior Thyroid Artery well lateral to the gland or carefully ligate its small branches on the surface of the gland

Branches

• Ascending Cervical Artery (or this can come off Thyrocervical Trunk)
• Small Pharyngeal branches
• Oesophageal branches
• Tracheal branches
• Inferior Laryngeal artery
  • Inferior Laryngeal Artery ascends with the Recurrent Laryngeal Nerve