Parapharyngeal space

Last revised by Craig Hacking on 21 Feb 2024

The parapharyngeal space (PPS), also known as the prestyloid parapharyngeal space, is a deep compartment of the head and neck around which most other suprahyoid fascial spaces are arranged. It consists largely of fat, neurovascular structures, and, in some definitions, the retromandibular part of the deep lobe of the parotid gland.

Two naming conventions exist in the literature. In the first definition, familiar to most head and neck surgeons, the parapharyngeal space is divided into prestyloid and poststyloid (retrostyloid) compartments 1-3,10. In the second definition, introduced by some radiologists, the prestyloid parapharygeal space is simply termed the parapharyngeal space, and the poststyloid pharapharygeal space is termed the carotid space 4-6. The latter facilitates differential diagnosis and is used in this article.

Other terms for the parapharyngeal space include the lateral pharyngeal spacepharyngomaxillary space, and even less commonly pterygomaxillary spacepterygopharyngeal spaceperipharyngeal space, and pharyngomasticatory space 1. The term pterygomandibular space has rarely been used for this location, but this term is best reserved for the subcompartment of the masticator space instead.

The parapharyngeal space is shaped like an inverted pyramid, with its base at the skull base, with its apex inferiorly pointing towards the greater cornu of the hyoid bone 2.

Lymph nodes and muscle are not included in the radiological definition of the parapharyngeal space.

The parapharyngeal space has complex fascial margins occupying the space between the muscles of mastication and the muscles of deglutition 1-6:

The parapharyngeal space appears triangular in the axial plane with density/signal consistent with fat.

Knowledge about the displacement patterns of fat within the parapharyngeal space will aid in the localization of lesions within adjacent deep spaces of the head and neck. A lesion arising in the: 

In contrast, a lesion primarily involving the parapharyngeal space will displace the carotid space posteriorly and the pharynx medially.

Lesions involving the (prestyloid) parapharyngeal space include 7:

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