Retropharyngeal space

The pharynx extends from the base of the skull to the inferior border of the cricoid cartilage.
The nasopharynx lies in front of the atlas. The oropharynx lies in front of the second and third cervical vertebrae. The laryngopharynx is related to the bodies of the 4th to 6th cervical vertebrae.
The retropharyngeal space is a potential space between the visceral unit of the neck anteriorly and the vertebral unit posteriorly. It extends from the base of the skull down to the superior mediastinum. It contains loose connective tissue to allow a degree of up-and-down movement of the pharynx during swallowing.

Infection results in difficulty in speaking and swallowing. Infection may spread inferiorly down the neck and into the thorax, involving the mediastinum (mediastinitis).
Massive infections of the upper respiratory tract or dental origin can break through into the retropharyngeal and alar spaces and track down to the mediastinum below, resulting in infection and inflammation of the mediastinum (mediastinitis).