The Paraglottic Space (PGS)

The paraglottic space (PGS):
- Is a bilateral, deep fascial compartment of the larynx:
  - Filled with fat and loose connective tissue
- Definition:
  - The paraglottic space (PGS) is a fat- and muscle-containing connective tissue compartment of the larynx:
    - Whose greatest clinical importance is:
      - As a preferential pathway for the spread of laryngeal cancers:
        
        Particularly transglottic tumors
    - As a prognostic and surgical planning determinant
  - It surrounds the laryngeal ventricle:
    - Lies deep to the true and false cords:
      - Between the mucosa and inner surface of the thyroid cartilage:
        
        It communicates directly with the preepiglottic space:
        
        Allowing tumor to move rapidly between compartments
  - It spans the supraglottic, glottic, and subglottic regions:
    - Playing a critical role in clinical oncology:
      - Because it acts as a primary, hidden pathway for the “transglottic” spread of laryngeal cancers
Anatomical Boundaries
- It was first described by:
  - Tucker and Smith in 1962
- The paraglottic space is a tetrahedral-shaped compartment bounded by several cartilaginous and fibroelastic structures:
  - Anterolaterally:
    - The inner surface of the thyroid cartilage
  - Superomedially:
    - The quadrangular membrane:
      - Which separates it from the false vocal folds
    - The space is continuous with (or, in some specimens, separated by a collagenous septum from) the preepiglottic space
  - Inferomedially:
    - The conus elasticus:
      - Which separates it from the subglottis
  - Posteriorly / Posterolaterally / Dorsally:
    - The mucosal lining of the piriform sinus
  - Anteriorly:
    - It communicates directly with the pre-epiglottic space
Content of the Space:
- The paraglottic space houses several vital neurovascular and muscular structures embedded within its protective layer of loose areolar and adipose tissue:
  - Adipose tissue:
    - Abundant fat:
      - That makes the space highly visible on CT and MRI scans
  - Intrinsic laryngeal muscles:
    - Including the thyroarytenoid, lateral cricoarytenoid, and posterior cricoarytenoid muscles
  - Blood vessels and nerves:
    - Glands, blood vessels, and branches of the superior and inferior laryngeal nerves
Clinical Significance:
- The primary clinical importance of the paraglottic space:
  - Lies in laryngeal oncology and tumor staging:
    - Transglottic Spread:
      - Because the PGS crosses the level of the laryngeal ventricle without physical barriers:
        
        A squamous cell carcinoma originating in the true vocal cords can easily migrate vertically through this space into the false vocal cords (or vice versa):
        
        This is known as transglottic spread
    - Cancer Staging:
      - Invasion of the inferior paraglottic space can limit vocal fold mobility
      - In the TNM staging system, tumor invasion into the paraglottic space:
        
        Automatically elevates a glottic or supraglottic laryngeal cancer to a T3 stage:
        
        Altering the treatment trajectory from localized therapy to systemic options or extensive surgery
    - Surgical Planning:
      - Knowledge of the paraglottic space borders is vital for performing voice-sparing, partial laryngectomies
      - If a tumor completely infiltrates this space:
        
        A total laryngectomy may be required to ensure clean margins

References:
- Joo YH, Park JO, Cho KJ, Kim MS. Relationship between paraglottic space invasion and cervical lymph node metastasis in patients undergoing supracricoid partial laryngectomy. Head Neck. 2012.
- Tamaki A, Miles BA, Lango M, Kowalski L, Zender CA. AHNS Series: Do you know your guidelines? Review of current knowledge on laryngeal cancer. Head Neck. 2018.
- Reidenbach MM. The Paraglottic Space and Transglottic Cancer: Anatomical Considerations. Clin Anat. 1996.
- Reidenbach MM. Borders and Topographic Relationships of the Paraglottic Space. Eur Arch Otorhinolaryngol. 1997.
- Joo YH, Park JO, Cho KJ, Kim MS. Relationship between paraglottic space invasion and cervical lymph node metastasis in patients undergoing supracricoid partial laryngectomy. Head Neck. 2012.
- Ferrari M, Schreiber A, Mattavelli D, et al. Surgical anatomy of the parapharyngeal space: Multiperspective, quantification-based study. Head Neck. 2019.
- Wang XR, Wang H, Gao Y, et al. Study on the Ultrasonic Characteristics of the Paraglottic Space at the Glottic Level in Normal Adults. Head Neck. 2026.
- Virós Porcuna D, Pollán Guisasola CM, Viña Soria C, et al. Transoral robotic parapharyngeal space dissection. Head Neck. 2024.
- Mohamed A, Paleri V, George A. A cadaveric study quantifying the anatomical landmarks of the facial artery and its parapharyngeal branches for safe transoral surgery. Head Neck. 2019.
- Hearn MW, Vogel CT, Laughlin RM, et al. Review of Spaces. Atlas of Operative Oral and Maxillofacial Surgery. 2022.
- Dammann F, Wartenberg J. Diseases of the Head and Neck. Radiology-Nuclear Medicine Diagnostic Imaging. 2023.