Larynx Anatomy - Cartilages, Ligaments, Membranes, and Joints

🧠 Anatomy of the Larynx – Part 2: Cartilages, Ligaments, Membranes, and Joints

🦴 Laryngeal Cartilages

The laryngeal framework consists of six cartilages:

• Three unpaired: Epiglottis, Thyroid cartilage, Cricoid cartilage
• Three paired: Arytenoid, Corniculate, and Cuneiform cartilages

🔹 1- Epiglottis

• Type: Elastic fibrocartilage

• Shape: Thin, leaf-like

• Location: Forms the anterior wall of the laryngeal inlet; projects behind the tongue and hyoid bone

• Attachments:

  • Inferior: Thyroepiglottic ligament (to thyroid cartilage below thyroid notch)
  • Anterior: Hyoepiglottic ligament (to hyoid bone)
  • Lateral: Aryepiglottic folds (to arytenoid apex)
  • Posterior surface: Reflects mucosa to tongue forming median and lateral glossoepiglottic folds

• Surfaces:

  • Anterior (lingual)
  • Posterior (laryngeal)

What is Pre-epiglottic Space of Boyer? What is it's clinical importance?

Why is viewing the anterior commissure difficult while performing indirect laryngoscopy?

🔹 2- Thyroid Cartilage

• Largest of all laryngeal cartilages

• Structure: Two laminae fused in the midline (forming the Adam's apple)

• Angle: 90° in males, 120° in females

• Processes:

  • Superior Cornu
  • Inferior Cornu

• Attachments:

  • Outer surface: Oblique line → thyrohyoid, sternothyroid, inferior constrictor

  • Inner surface:

    • Above: Thyroepiglottic ligament
    • Midzone: Vocal and vestibular ligaments, thyroarytenoid and vocalis muscles

  • Borders:

    • Superior: Thyrohyoid membrane
    • Inferior: Cricothyroid ligament

🔹 3- Cricoid Cartilage

• Only complete ring in the airway

• Structure: Broad lamina posteriorly, narrow arch anteriorly

• Articulations:

  • Cricothyroid joint
  • Cricoarytenoid joint

• Attachments:

  • Ligaments: Cricotracheal, cricothyroid, and cricovocal
  • Muscles:
    • Posterior surface: Posterior cricoarytenoid
    • Midline ridge: Longitudinal pharyngeal muscles

What is the key functional unit of larynx?

🔹 4- Arytenoid Cartilage

• Shape: Pyramidal with base and apex

• Processes:

  • Vocal process
  • Muscular process

• Surfaces:

  • Anterolateral
  • Medial
  • Posterior
  • Base
  • Apex

What are the attachments of different parts of Arytenoid cartilage?

🔹 5- Corniculate Cartilage

• Also called: Cartilage of Santorini

• Shape: Small conical nodules located in the posterior part of aryepiglottic fold

• Articulates with Apex of arytenoid

🔹 6- Cuneiform Cartilage

• Also called: Cartilage of Wrisberg

• Shape: Elongated, rod-shaped

• Location: Lies in aryepiglottic fold; provides structural support

🧵 Ligaments and Membranes of the Larynx

🔗 Extrinsic Ligaments (connect larynx to external structures):

• Thyrohyoid Membrane: Between thyroid cartilage and hyoid.

What structures pierce the Thyrohyoid membrane?

• Cricotracheal Ligament: Connects cricoid cartilage to first tracheal ring.

• Hyoepiglottic Ligament: Connects hyoid to epiglottis, divides epiglottis into suprahyoid and infrahyoid parts.

🔗 Intrinsic Ligaments (connect internal laryngeal cartilages):

These form the fibroelastic membrane beneath the mucosa, subdivided into:

1- Quadrangular Membrane:

• From epiglottis → arytenoids
• Lower margin → forms vestibular ligament (false vocal cord)
• Upper margin → aryepiglottic fold

2- Cricovocal Membrane:

• From cricoid → thyroid cartilage
• Upper free border → vocal ligament (true vocal cord)
• Together with its counterpart forms the Conus Elasticus
• Anterior thickening → Cricothyroid ligament

3- Thyroepiglottic Ligament: Connects thyroid cartilage to epiglottis.

⚙️ Joints of Larynx

🔸 1- Cricoarytenoid Joint

• Location: Formed between the base of the arytenoid cartilage and a facet on the upper border of the lamina of the cricoid cartilage, enclosed by a capsular ligament.

• Type: Synovial joint

• Movements:

  • Rotatory Movement (around a vertical axis)
  • Gliding (Sliding) Movement

🔸 2- Cricothyroid Joint

• Location: Formed between the inferior cornu of the thyroid cartilage and a facet on the side of the cricoid cartilage.

• Type: Synovial joint

• Movement: Allows rotational movement of the cricoid cartilage around a transverse axis.

✅ Summary Table