The Parapharyngeal Space

The parapharyngeal space:
- Also known as the:
  - Prestyloid parapharyngeal space:
    - Is one of the seven deep compartments of the head and neck
It consists largely of:
- Fatty areolar tissue
- Contains branches of the:
  - Trigeminal nerve
- Deep blood vessels
Two naming conventions exist in the literature:
- In the first definition:
  - Familiar to most head and neck surgeons, the parapharyngeal space is divided into:
    - The prestyloid compartment and
    - Poststyloid (retrostyloid) compartment
- 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
Gross anatomy:
- The parapharyngeal space:
  - Is shaped like a pyramid:
    - An inverted pyramid with:
      - Its base:
        At the skull base
      - Its apex:
        Inferiorly:
        Pointing to the greater cornu of the hyoid bone
- Contents:
  - Fat:
    - Main component
  - Deeps blood vessels:
    - Internal maxillary artery
    - Ascending pharyngeal artery
    - Pterygoid venous plexus:
      - Only small portion:
        Because it is mainly within:
        The masticator space
  - Nerve:
    - Small branch of the mandibular division of the trigeminal nerve (cranial nerve V):
      - Supplying the tensor veli palatini muscle
  - Salivary glands – depends on the definition:
    - Some say that it contains no salivary glands, others
    - Minor or ectopic salivary gland / rests
    - Retromandibular portion of the deep lobe of parotid gland
  - Lymph nodes
Boundaries:
- The parapharyngeal space has complex fascial margins:
  - Occupying the space between the muscles of mastication and the muscles of deglutition:
    - Superior margin:
      - Base of skull
    - Inferior margin:
      - Greater cornu of the hyoid bone:
        Although some state the space functionally ends higher:
        With the styloglossus muscle:
        At the level of the angle of the mandible
    - Medial margin:
      - Middle (pretracheal) layer of the deep cervical fascia:
        Covering the:
        Superior pharyngeal constrictor
        Levator palatini muscle and
        Tensor veli palatini muscle
    - Lateral margin:
      - Investing fascia (superficial layer) of the deep cervical fascia:
        Covering the deep lobe of the parotid
    - Anterior margin:
      - Investing fascia (superficial layer) of the deep cervical fascia:
        Covering the medial pterygoid muscle
    - Posterior margin:
      - Prevertebral layer of the deep cervical fascia
Relations:
- Medial:
  - To the masticator space
- Lateral:
  - To the pharyngeal mucosal space
- Anterior:
  - To the prevertebral space
- Posterior:
  - To the medial pterygoid