Joints and ligaments · Head and neck
Quadrangular membrane !
The quadrangular membrane is a thin sheet in the upper wall of the larynx; its lower edge forms the vestibular fold, or false vocal cord.
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What it is
A thin sheet in the upper larynx wall.
What it does
Its lower edge forms the false vocal fold.
Key facts
- Attaches
- Sides of the epiglottis to the arytenoid cartilages
- Function
- Wall of the laryngeal vestibule; its lower free edge is the vestibular (false) fold
Relations
- Above
- Aryepiglottic fold: its upper margin with the aryepiglottic muscle and mucosa
- Below
- Laryngeal ventricle and its saccule, then the vocal folds
- Lateral
- Paraglottic space and the thyroid cartilage lamina; across the aryepiglottic fold, the pyriform recess
- Medial
- Mucosa of the laryngeal vestibule
How to find it
Not palpable. On laryngoscopy its upper edge is the aryepiglottic fold running from the epiglottis back to the arytenoid, and its lower edge is the vestibular (false) fold, just above the ventricle and the true vocal fold.
On imaging
On coronal CT or MRI the false fold holds fat in the paraglottic space while the true fold is muscle density; this marks the level of the ventricle and helps stage tumours as supraglottic or glottic.
Clinical notes
- Ventricular (false fold) phonation: the vestibular folds vibrate instead of or with the true folds, giving a rough, low voice, sometimes as compensation after true fold damage
- Supraglottic laryngectomy removes the region above the ventricle, this membrane included, while keeping the true vocal folds
- Severe laryngomalacia can be treated by supraglottoplasty, which trims short or redundant aryepiglottic folds so they stop falling into the airway on breathing in
Test yourself
Think of the answer, then tap the question to see it.
What do the upper and lower free edges of the quadrangular membrane form?
The upper edge is the aryepiglottic ligament in the aryepiglottic fold; the lower edge is the vestibular ligament of the false vocal fold.
What lies between the quadrangular membrane and the conus elasticus?
The laryngeal ventricle; together the two make up the fibroelastic membrane of the larynx.
Why do supraglottic cancers reach the neck nodes earlier than early glottic cancers?
The supraglottis, supported by the quadrangular membrane, has many lymphatics, so spread to nodes is early and often bilateral.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- membrana quadrangularis TA2 1658
- Official Spanish (DeCS)
- Membrana cuadrangular
- English (TA2)
- Quadrangular membrane
Sources: Terminologia Anatomica (TA2); Anatomy, Head and Neck, Larynx Vocal Cords; Anatomy, Head and Neck: Larynx Cartilage; Anatomy, Head and Neck: Larynx.
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Representative model, for educational purposes only.
