Larynx Anatomy - Parts, Blood Supply, Lymphatic Drainage of Larynx
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🗂️ Anatomy of Larynx – Part 1: Parts, Extent, Blood Supply, Lymphatic Drainage
📏 Measurements of the Larynx
| Measurement | Male | Female |
|---|---|---|
| Length | 44 mm | 36 mm |
| Transverse Diameter | 43 mm | 41 mm |
| Anteroposterior Diameter | 36 mm | 26 mm |
| Circumference | 136 mm | 112 mm |
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
| Vein | Drains Into |
|---|---|
| Superior Laryngeal Vein | Internal jugular vein (via superior thyroid/facial vein) |
| Inferior Laryngeal Vein | Brachiocephalic vein (via inferior thyroid vein) |
| Middle Thyroid Vein | Internal jugular vein (some drainage) |
🧫 Mucosal Lining of Larynx
🧬 Epithelium Types
| Region | Epithelium Type |
|---|---|
| Most of larynx | Ciliated columnar epithelium |
| Vocal cords, upper vestibule, posterior epiglottis | Stratified squamous epithelium |
💧 Mucous Glands
- Present throughout the larynx
- Especially numerous on:
- Posterior surface of epiglottis
- Posterior AE folds
- Saccules
- Absent in the true vocal cords
📝 All the topics and questions mentioned in this post are explained in detail in my ENT notes - built for exam success and clinical understanding. Get full access by purchasing the notes.