Larynx Anatomy - Parts, Blood Supply, Lymphatic Drainage of Larynx

🗂️ Anatomy of Larynx – Part 1: Parts, Extent, Blood Supply, Lymphatic Drainage

📏 Measurements of the Larynx

Note: Differences are negligible in children but become significant after puberty due to hormonal changes in males (growth of thyroid cartilage, deepening of voice, etc.).

📍 Extent of Larynx

• Extends from the laryngeal inlet (upper limit) to the lower border of the cricoid cartilage
• Lies opposite C3 to C6 vertebrae
• The larynx sits higher in females than in males

🧩 Parts of Larynx

The larynx is divided into three parts by the false and true vocal cords:

1️⃣ Supraglottis

• Begins at the epiglottis and aryepiglottic (AE) folds
• Extends to the apex of the laryngeal ventricle
• Includes: Epiglottis, AE folds, arytenoids

2️⃣ Glottis

• Extends from apex of laryngeal ventricle to 1 cm below the free edge of vocal cords
• Includes: True vocal cords, anterior and posterior commissures

3️⃣ Subglottis

• From 1 cm below the vocal cords to the lower border of the cricoid cartilage (C6)

🧬 Lymphatic Drainage of Larynx

Divided based on position relative to the vocal cords:

🔼 Supraglottic Larynx

• Drainage accompanies superior laryngeal vein
• Pierces thyrohyoid membrane
• Drains into upper deep cervical nodes

⛔ Vocal Cords

• No lymphatics

Why do Vocal fold cancers not have early spread to lymph nodes?

🔽 Infraglottic Larynx

• Pierces cricothyroid membrane
• Drains into prelaryngeal (Delphian) and pretracheal nodes
• Eventually reaches lower deep cervical nodes

🩸 Blood Supply of Larynx

🔀 Arterial Supply

• Superior Laryngeal Artery
• Cricothyroid Artery
• Inferior Laryngeal Artery

🔍 Course of Major Arteries

➤ Superior Laryngeal Artery

• Pierces thyrohyoid membrane with lymphatics and internal laryngeal nerve
• Enters at anterior end of AE fold

➤ Inferior Laryngeal Artery

• Ascends with recurrent laryngeal nerve
• Enters behind inferior constrictor

➤ Cricothyroid Artery

• Crosses upper cricothyroid ligament
• Has up to five branches — important in anterior commissure surgeries

🧵 Venous Drainage

🧫 Mucosal Lining of Larynx

🧬 Epithelium Types

💧 Mucous Glands

• Present throughout the larynx
• Especially numerous on:
  • Posterior surface of epiglottis
  • Posterior AE folds
  • Saccules
• Absent in the true vocal cords