Defining the poststyloid parapharyngeal space from surrounding deep neck spaces and lesions that may arise within it.

The parapharyngeal space (PPS) is an inverted pyramid shaped space that extends from the skull base to the level of the hyoid bone, on either side of the pharynx (1). In traditional surgical anatomy, the PPS is divided into two compartments by the styloid process and the tensor-vascular-styloid (TVS) fascia. The compartment anterior to the styloid process (or pre-styloid PPS) contains mostly fat and the compartment posterior to the styloid process (or post-styloid PPS) contains the major vascular structures. More recently, Harnsberger described the post-styloid...

When reporting on a lesion in the suprahyoid neck, it is important to determine the space of origin. This helps to narrow the possible differential diagnosis depending on the structures present within that space (3). The displacement of the parapharyngeal fat space is one well described method used to do this. However, the effect of the lesion on the styloid process and carotid sheath vessels are other helpful clues to look for. The styloid process is a therefore a useful landmark to review. The styloid...

The understanding of the structure and relations of the poststyloid PPS aids in the diagnosis of deep neck space lesions occurring in this region.

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