Parapharyngeal Space Spread — MFDS Part 1 MCQ

Correct answer: A — Posterior spread into the retropharyngeal and danger spaces

The correct answer is A. The parapharyngeal space communicates posteriorly with the retropharyngeal region. Infection can enter the danger space, which lies between the alar and prevertebral fasciae and extends inferiorly into the posterior mediastinum. This creates a route for descending deep-neck infection and potentially fatal mediastinitis. Spread into the sublingual space would principally involve the floor of the mouth, while spread into the infratemporal fossa produces superior rather than thoracic extension. The peritonsillar and parotid spaces may be involved in regional deep-neck infection, but neither provides the characteristic direct descending pathway to the mediastinum. The original keyed answer was therefore correct, but its description of the retropharyngeal space alone extending into the posterior mediastinum required anatomical clarification.

Reference: BMJ Case Reports, “Descending necrotising mediastinitis: a rare entity in children,” 2024. https://pubmed.ncbi.nlm.nih.gov/38453221/