---
title: "Anatomy of Internal Nose"
description: "Notes on the Anatomy of Internal nose - vestibule, nasal valves, boundaries of the nasal cavity, and clinical relevance - for medical students and ENT residents."
source: "The ENT Resident"
author: "Dr. Mausumi Das"
canonical_url: "https://www.theentresident.com/ent-notes-lectures/nose-anatomy"
categories: ["Rhinology"]
video: "https://www.youtube.com/watch?v=SbgI3Iv0ot4"
image: "https://media.theentresident.com/og-images/nose-anatomy.png"
---

# Anatomy of Internal Nose

Notes on the Anatomy of Internal nose - vestibule, nasal valves, boundaries of the nasal cavity, and clinical relevance - for medical students and ENT residents. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=SbgI3Iv0ot4

In this post, we explore the **internal nose**, including its division, the **nasal vestibule**, **nasal valves**, and the **boundaries of the nasal cavity proper**.

### 🧭 Division of Internal Nose

The internal nose is divided into **right and left nasal cavities** by the **nasal septum** (a midline structure).

Each nasal cavity:

- **Communicates anteriorly** with the **external environment** via the **nares (nostrils)**

- **Communicates posteriorly** with the **nasopharynx** through the **posterior nasal aperture** (*choana*)

---

### 👃 Vestibule of the Nose

- **Most anterior and inferior** part of the nasal cavity

- Lined by **keratinized stratified squamous epithelium**

- Contains **vibrissae** (coarse nasal hairs), **sebaceous glands**, and **sweat glands**

- Upper limit marked by the **limen nasi** (nasal valve)

### 🚪 Nasal Valves

Nasal valves are **critical anatomical zones** regulating nasal airflow. 

They are divided into:


**🔹 External Nasal Valve**

>What are the boundaries of External Nasal Valve?

**Clinical Significance:**
- Weakness or deformity of any boundary → **narrowing or collapse** of external nasal valve
- Collapse worsens during **inspiration**, leading to **nasal obstruction**


#### 🔹 Internal Nasal Valve

- **Narrowest cross-sectional area** of the nasal airway
- **Key site for resistance regulation during inspiration**

>What are the boundaries of Internal Nasal Valve?

>What is Cottle's test? What does it signify?

---

### 🏛 Boundaries of the Nasal Cavity Proper

Each nasal cavity has:

- **Roof**
- **Floor**
- **Medial wall** → Nasal septum
- **Lateral wall** 

#### 🔸 **Roof of Nasal Cavity**

**Formed by:**

1. **Anterior slope** → Nasal bones + Nasal spine of frontal bone
 
2. **Middle horizontal part** → Cribriform plate of ethmoid bone  

3. **Posterior slope** → Body of sphenoid bone

>What is the surgical importance of the sloping nature of the roof?

**🧠 Olfactory Fossa**

Olfactory fossa lies above cribriform plate

**Formed by:**
- Horizontal & vertical lamellae of cribriform plate
- Orbital plate of frontal bone

>What is **Keros Classification**? 

>What is **Gyrus Rectus Sign** and which disease do you see it in?

#### 🔸 **Floor of Nasal Cavity**

- Concave side-to-side, flat anteroposteriorly
- Horizontally oriented

**Formed by:**

- **Anterior ¾** → Palatine process of maxilla  

- **Posterior ¼** → Horizontal plate of palatine bone

🕳 **Incisive Canal** (12 mm posterior to anterior floor)

>What structures pass through the incisive canal?

---

##  Summary

| Region | Key Features |
| --- | --- |
| Vestibule | Skin-lined, contains vibrissae and sebaceous glands |
| External Nasal Valve | Lateral alar rim, medial septum, inferior nasal sill |
| Internal Nasal Valve | Septum + upper lateral cartilage + head of inferior turbinate |
| Roof | Nasal bones, cribriform plate, sphenoid |
| Floor | Palatine process of maxilla + horizontal palatine bone |
| Olfactory Fossa | Site of olfactory nerve entry, prone to CSF leaks if damaged |

---

## About This Note

This free ENT note on Anatomy of Internal Nose 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/nose-anatomy

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

## Related Notes by Category

- Rhinology: https://www.theentresident.com/ent-notes-lectures/category/rhinology.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.

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