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Danger Space — MFDS Part 1 MCQ

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HardAnatomy (Head & Neck)Danger SpaceMFDS Part 1

An odontogenic deep-neck infection breaches the alar fascia and enters the potential space bounded anteriorly by the alar fascia and posteriorly by the prevertebral fascia. Which inferior course accounts for the clinical importance of this danger space?

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Correct answer: A — Posterior mediastinum, reaching the level of the diaphragm

The correct answer is A. The described potential space is the danger space, situated between the alar fascia anteriorly and the prevertebral fascia posteriorly. It extends from the skull base into the posterior mediastinum as far as the diaphragm, providing a direct route for deep-neck infection to cause descending mediastinitis. The true retropharyngeal space lies anterior to the alar fascia and has a shorter inferior extent, making B and E incorrect. The danger space does not primarily descend through the anterior mediastinum or within the carotid space, excluding C and D. Its extensive cervicothoracic continuity explains its particular clinical significance.

Reference: Mnatsakanian A, Minutello K, Black AC, Bordoni B. Anatomy, Head and Neck, Retropharyngeal Space. StatPearls [Internet], January 2026 edition. https://pubmed.ncbi.nlm.nih.gov/30725729/