What are the anatomical boundaries of the supraglottic larynx?

Anatomical Boundaries of the Supraglottic Larynx

The supraglottic larynx encompasses the structures above the true vocal folds, specifically including the arytenoid regions, epiglottis, and false vocal folds. 1, 2

Anatomical Definition

The supraglottic region is one of three distinct anatomical divisions of the larynx, accounting for 30-35% of all laryngeal cancers. 1, 3 The key anatomical boundaries are:

Superior Border

• The supraglottic larynx extends superiorly to include the epiglottis and aryepiglottic folds 1
• The tip of the epiglottis represents the uppermost extent of this region 1

Inferior Border

• The inferior boundary is the plane of the true vocal folds (glottis) 1, 2
• The laryngeal ventricle serves as the anatomical landmark separating the supraglottic from the glottic region 4

Included Structures

• False vocal folds (ventricular folds) 1, 2
• Arytenoid regions including the arytenoid cartilages and their associated soft tissues 1, 2
• Epiglottis in its entirety 1, 2
• Aryepiglottic folds 1
• Pre-epiglottic space (relevant for tumor staging) 1

Clinical Significance for Treatment Planning

Radiation Field Considerations

• The supraglottic region has distinct lymphatic drainage patterns with up to 60% risk of occult neck metastases, unlike the sparsely drained glottic region 1
• Treatment planning must account for the fact that supraglottic tumors remain confined above the ventricle in most cases, with local control rates of 80.6-98% achievable with horizontal supraglottic laryngectomy 4

Important Anatomical Barrier Concept

• While embryologically distinct from the glottis, there is no true anatomical barrier preventing tumor spread between supraglottic and glottic regions 4, 5
• Tumors appearing both above and below the glottic level typically arrive there by encircling the ventricle rather than crossing it directly 4
• Tumor extension posterior to the ventricle or onto the arytenoid cartilage contraindications conventional supraglottic laryngectomy 4

Staging Implications

• T1-T2 favorable supraglottic lesions are defined as superficial tumors with preserved cord mobility and/or tumors of the aryepiglottic fold with minimal pyriform sinus involvement 1
• T3 supraglottic tumors with minimal or moderate pre-epiglottic invasion may be candidates for organ-preserving surgery 1