Retropharyngeal space

The retropharyngeal space is a potential space of the head and neck, bounded by the buccopharyngeal fascia anteriorly and the prevertebral fascia posteriorly. 

Because serious infections of teeth can spread down this space into the posterior mediastinum, it is often confused with the danger space. The danger space is actually between the alar fascia and the prevertebral fascia and extends from the cranial base above to the level of the diaphragm.

Boundaries:

• Superior: Base of the skull
• Inferior: Superior mediastinum (the termination of the true RPS along the upper thoracic spine (T1-T6) is variable based on where the alar fascia joins and fuses with the visceral fascia.)
• Lateral: Carotid sheath
• Anterior: Buccopharyngeal fascia
• Posterior: Alar fascia