Imaging of the parapharyngeal space

The parapharyngeal space (PPS) is a deep fascial space in the suprahyoid neck, shaped like an inverted cone. The tensor vascular styloid fascia divides it into prestyloid compartment that mainly contains fat and retrostyloid compartment that contains the carotid sheath and its content. Most lesions in the prestyloid PPS either bulge into it from adjacent neck spaces or push it. The pattern of parapharyngeal fat displacement is used for localization of lesions in the deep neck. Primary lesions of the prestyloid PPS are rare and mostly benign. Tumors of the retrostyloid compartment usually grow from the carotid sheath content and are mostly of neurogenic origin. Owing to the central location of the space, it may serve as a critical path of tumoral or infectious spread from one neck space to another. In this review, we describe the basic anatomy of the PPS and present the radiological approach to lesions involving it.