---
title: "Nerve Supply of Larynx - Recurrent Laryngeal Nerve and Superior Laryngeal Nerve"
description: "A guide to the Nerve Supply of Larynx for medical students and ENT residents."
source: "The ENT Resident"
author: "Dr. Mausumi Das"
canonical_url: "https://www.theentresident.com/ent-notes-lectures/recurrent-superior-laryngeal-nerve"
categories: ["Larynx and Trachea"]
video: "https://www.youtube.com/watch?v=SeRXfrsKwVc"
image: "https://media.theentresident.com/og-images/recurrent-superior-laryngeal-nerve.png"
---

# Nerve Supply of Larynx - Recurrent Laryngeal Nerve and Superior Laryngeal Nerve

A guide to the Nerve Supply of Larynx for medical students and ENT residents. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=SeRXfrsKwVc

## 🔌 Nerve Supply of Larynx – Recurrent Laryngeal Nerve and Superior Laryngeal Nerve

### 🧠 Overview of Laryngeal Innervation
The **vagus nerve (cranial nerve X)** gives rise to both the **recurrent laryngeal nerve** and the **superior laryngeal nerve**, which together supply the larynx.

#### ⚙️ **Motor Supply of Larynx**
All intrinsic muscles of the larynx are supplied by the **recurrent laryngeal nerve**, _except_ **Cricothyroid**, which is supplied by the **External branch** of the **Superior laryngeal nerve**.

#### 👂 **Sensory Supply of Larynx**
- **Above the vocal cords**: Supplied by the **Internal branch** of the **Superior laryngeal nerve**.
- **Below the vocal cords**: Supplied by the **Recurrent laryngeal nerve**.

---

### 🔄 Recurrent Laryngeal Nerve (RLN)

**🧬 Origin**

- **Right RLN**:
  - Arises at the root of the neck from the **right vagus nerve** (level of **T1**).
  - Loops around the **first part of the right subclavian artery**.

- **Left RLN**:
  - Arises in the thorax as the **left vagus** crosses the **aortic arch** (level of **T3**).
  - Loops around the **arch of the aorta**, **posterior to ligamentum arteriosum**.

**🛣️ Course**

- Ascends in the **tracheoesophageal groove**.
- Passes **deep to the lower border of the inferior constrictor**.
- Enters the larynx **behind the cricothyroid joint**.

**🧪 Nerve Supply**

- **Motor**: All intrinsic laryngeal muscles except cricothyroid.

- **Sensory**: Mucosa **below the vocal cords**.

**🧫 Developmental Basis**

- **Left RLN** hooks under the **arch of aorta** due to persistence of the **dorsal part of the 6th aortic arch** (ligamentum arteriosum).

- **Right RLN** hooks under the **4th aortic arch** (right subclavian artery), as the **5th and 6th arches regress**.

>Why is Recurrent Laryngeal Nerve longer in the left side than the right side?

>What is **Non-Recurrent Laryngeal Nerve**?

---

### 📡 Superior Laryngeal Nerve (SLN)

**🧬 Origin**

- Arises from the **inferior ganglion of vagus** in the neck.

- Receives a twig from the **superior cervical sympathetic ganglion**.

- Divides into:
  - **External branch** (Motor)
  - **Internal branch** (Sensory)

**🌿 Branches and Course**

🔧 **External Branch**

- **Supplies**: Cricothyroid muscle  
- **Travels with**: Superior thyroid artery  
- **Passes deep to**: Upper thyroid pole  

🌬️ **Internal Branch**

- **Pierces**: Thyrohyoid membrane  
- **Supplies**:
  - Mucosa **above the vocal cords**
  - Glands via **parasympathetic secretomotor fibers**

🧵 **Terminal Branches of Internal SLN:**

- **Superior branch** → Lingual surface of epiglottis  
- **Middle branch** → Aryepiglottic fold and vestibular folds  
- **Inferior branch** → Pyriform sinus and postcricoid region  
- **Forms anastomosis** with recurrent laryngeal nerve → **Galen's Anastomosis** (*purely sensory*)

>What is Human communicating nerve?

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### 📋 Summary Table

| Nerve | Branch | Motor Supply | Sensory Supply |
| --- | --- | --- | --- |
| Recurrent Laryngeal Nerve | From Vagus (X) | All intrinsic muscles except cricothyroid | Below vocal cords |
| Superior Laryngeal Nerve – External | From Vagus (X) | Cricothyroid | — |
| Superior Laryngeal Nerve – Internal | From Vagus (X) | — | Above vocal cords, supraglottic larynx |

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## About This Note

This free ENT note on Nerve Supply of Larynx - Recurrent Laryngeal Nerve and Superior Laryngeal Nerve was written by Dr. Mausumi Das and is paired with a corresponding video lecture.

Canonical page of this note: https://www.theentresident.com/ent-notes-lectures/recurrent-superior-laryngeal-nerve

When citing or referencing this content, please credit The ENT Resident and link to the canonical page above.

## Related Notes by Category

- Larynx and Trachea: https://www.theentresident.com/ent-notes-lectures/category/larynx-and-trachea.md

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The ENT Resident is an educational website and resource library created by Dr. Mausumi Das (MS ENT) for ENT residents, ENT postgraduates preparing for exams, and MBBS students.

Dr. Mausumi Das writes the notes, draws the diagrams, and records the lectures herself.

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