Larynx Anatomy - Spaces and Compartments of Larynx

🎙️ Larynx Anatomy – Part 3: Spaces and Compartments

🧭 Spaces of the Larynx

The spaces in the larynx are important as potential pathways for tumor spread.

Understanding them has critical implications for oncologic management and surgical planning.

🔸 1- Pre-Epiglottic Space of Boyer

• Shape: Wedge-shaped; apex directed inferiorly

• Boundaries:

  • Anterior: Hyoid bone, thyrohyoid membrane, thyroid cartilage
  • Posterior: Infrahyoid part of epiglottis, quadrangular membrane
  • Superior: Hyoepiglottic ligament
  • Lateral: Communicates freely with paraglottic space

• Contents: Fat, areolar tissue, lymphatics

What is the surgical importance of Pre-Epiglottic Space of Boyer?

🔸 2- Paraglottic Space (Tucker’s Space)

• Boundaries:

  • Lateral: Thyroid cartilage
  • Medial: Quadrangular membrane (above), conus elasticus (below)
  • Posterior: Pyriform sinus mucosa
  • Anterior: Continuous with pre-epiglottic space

• Contents: Laryngeal ventricle, saccule

What is the surgical importance of Paraglottic Space?

🔸 3. Reinke’s Space

• Location: Just beneath the epithelium of the vocal folds

• Component of: Superficial layer of the lamina propria

• Boundaries:

  • Superior & Inferior: Arcuate lines
  • Anterior: Anterior commissure
  • Posterior: Vocal process of arytenoids

• Contents: Loose connective tissue

What is Reinke's Oedema?

🏛️ Compartments of the Larynx

The larynx is divided into three compartments by the Vestibular and Vocal folds.

🟨 1- Vestibule (Supraglottic Compartment)

• Upper compartment.
• Extent: From laryngeal inlet to vestibular folds

What are the boundaries of laryngeal inlet?

🟩 2- Ventricle (Middle Compartment / Sinus of Larynx)

• Location: Between vestibular and vocal folds

• Feature: Contains the saccule of Hilton

• Saccule:

  • Mucosal diverticulum that ascends between vestibular ligament and thyroid cartilage

What is Laryngocele?

🟥 3- Infraglottic Compartment

• Extent: From vocal folds to lower border of cricoid cartilage (~1 cm)

• Continuation: Into the trachea

🧩 Important Spaces Between Folds

🔹 Rima Vestibuli

• Space between vestibular folds

• Seen as a triangular gap when folds are apart

🔹 Rima Glottidis

• Space between the vocal folds and arytenoid cartilages

• Narrowest part of the laryngeal cavity

• Dimensions:

  • ~24 mm (males)
  • ~16 mm (females)

• Parts:

  • Anterior 3/5 (membranous): Phonatory glottis
  • Posterior 2/5 (cartilaginous): Respiratory glottis

What structures form the Phonatory glottis and Respiratory glottis?

🎭 Structure of Folds

🟣 Vestibular Folds (False Cords)

Formed by mucous membrane overlying:

• Vestibular ligament (from lower border of quadrangular membrane)
• Fibers of thyroarytenoid muscle
• Mucous glands

What are attachments of Vestibular folds?

🔵 Vocal Folds (True Cords)

📍 Extent and Attachments of the Vocal Folds

• Anterior: Middle of the thyroid cartilage angle
• Posterior: Vocal process of the arytenoid cartilages
• Supported by: Upper border of the conus elasticus

🧬 Histological Layers of the Vocal Folds

The vocal folds are layered structures, with each layer contributing to their vibratory properties.

From superficial to deep:

1️⃣ Epithelium

• Non-keratinized stratified squamous epithelium
• Provides a smooth surface and withstands mechanical stress

2️⃣ Lamina Propria

Divided into three layers:

• Superficial Layer (Reinke's Space)

  • Loose, gelatinous connective tissue
  • Allows for vibratory movement
  • Also known as Reinke’s space

• Intermediate Layer

  • Contains elastic fibers
  • Provides elasticity

• Deep Layer

  • Rich in collagen fibers
  • Provides strength and structure

Which layers form the Vocal Ligament?

3️⃣ Vocalis Muscle

• Forms the main body of the vocal fold
• Responsible for tension and fine control of the vocal folds during phonation

🧱 Regional Variations in Vocal Fold Structure

The structure of the vocal fold is not uniform along its entire length. There are three distinct areas where the tissue becomes denser and serves special functions:

1. Anterior Commissure Tendon (Broyles Ligament)
2. Anterior Macula Flava
3. Posterior Macula Flava

What is Broyles ligament?