eRadiograph Volume 7: Imaging of Oral Cavity | Page 148

Parapharyngeal Space Introduction This is a central fat filled space deep in the face. It is not surrounded by fascia but surrounded by fascial lined spaces. Since there is no fascial covering and it contains only fat, it is very mobile and can be easily displaced. Mass lesions in the adjacent fascially lined spaces displace the fat filled parapharyngeal space. Based on the direction of the displacement of this space the origin of the space from where the primary pathology is lying can be determined. Extent and Anatomy The parapharyngeal space extends from the petrous apex at the base of the skull inferiorly to the greater cornu of the hyoid. Inferiorly it is continuous with the fat of the posterior aspect of the submandibular space as there is no fascia separating the parapharyngeal space from the submandibular space. As a result pathological processes can pass freely between these two spaces. The parapharyngeal space lies lateral to the pharyngeal mucosal space, anterolateral to retropharyngeal space, anterior to the carotid space posteromedial to masticator space and medial to parotid space. If PPS is displaced Laterally – lesion is in Posteriorly – Anteriorly – Anterolaterally – Medially – Pharyngeal mucosal space Masticator space Carotid space Retropharyngeal space Parotid space It is important to differentiate a lesion arising primarily in the parapharyngeal space from a deep lobe parotid mass, this distinction is important as a surgeon will approach a primary parapharyngeal mass from a submandibular or oral route but a deep lobe parotid will be approached via a transparotid approach so facial nerve control is achieved. A lesion in the parapharyngeal space will have a thin crescent of fat along its lateral aspect whereas a lesion arising from the deep lobe of parotid would have a fat plane along its medial aspect. Contents The contents of the parapharyngeal space are fat, styloglosus, stylopharyn - geus muscles, internal maxillary artery, inferior alveolar, lingual and auriculotemporal nerves. 148 Parapharyngeal Space The parapharyngeal space is also a useful landmark for surgeons – as once they reach this space, they are then aware that just posterior are important vascular structures in the carotid space.