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What is The external opening of the branchial fistula is nearly always situated in the lower third of the neck near the anterior border of which of the following muscle and explain in detail?
Branchial fistula
• A branchial sinus or fistula (congenital type) is formed when the 2nd arch fails to fuse with the 5th arch or Epipericardial ridge. It represents a persistent second branchial cleft.
• Bursting of the branchial cyst or an inadvertent incision may lead to formation of acquired branchial fistula.
• The external opening of the fistula is nearly always situated in the lower third of the neck near the anterior border of the sternomastoid muscle.