The purpose of our educational exhibit is to: 1. Illustrate the normal radiologicanatomy of the retropharyngeal space. 2. Describe and illustrate disease processes thatcauseretropharyngeal fluid collection. 3. Discuss ways to differentiatethe different disease entities.

The retropharyngeal space (RPS) extends from the skull base to the uppermediastinum at T1 to T6 level. It is located posterior to the pharynx and esophagus and anterior to the perivartebral space (FIG 1). The space is surrounded anteriorly by the pharyngeal mucosal space; laterally by the parapharyngeal and carotid spaces and posteriorly by the danger space and perivertebral spaces. The space containes areolar fat in its suprahyoid and infrahayoid compartments .Lymph nodes are found only in the suprahyoid portion. The lymph nodes drain the...

Diagnosis of RPS edema: Knowledge of the normal RPS anatomy as detailed in the background section should facilitate the diagnosis of abnormal RPS edema. When analyzing cervical spine and neck images radiologist should look for the normal RPS fat (FIG 1), whenever edema is present instead of fat, itssourceshould be searched. Edema should be distinguished from abscess that usually has peripheral enhancement and exert mass effect. Intrapharyngeal / intra-esophageal fluids that have roundedconfiguration, should not be confused with RPS edema (FIG 3). The presence of...

Replacement of the RPS fat by fluid collection should prompt the radiologist to carefully scrutinize adjacent structure and correlate with the clinical information inorder to find the causative process. Table 1summarizesthe differentialdiagnosis possibilities discussed in this presentation. Care should be taken to exclude the possibility of a devastating infectious process that might spread to the mediastinum.

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