--- title: "Anatomy of the External Nose" description: "Notes on Anatomy of External nose -layers, framework, blood supply, innervation, lymphatics, and clinical relevance." source: "The ENT Resident" author: "Dr. Mausumi Das" canonical_url: "https://www.theentresident.com/ent-notes-lectures/external-nose-anatomy" categories: ["Rhinology"] video: "https://www.youtube.com/watch?v=iIC49WLDoxU" image: "https://media.theentresident.com/og-images/external-nose-anatomy.png" --- # Anatomy of the External Nose Notes on Anatomy of External nose -layers, framework, blood supply, innervation, lymphatics, and clinical relevance. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=iIC49WLDoxU This post is designed to help **MBBS and ENT students** understand the external nasal anatomy in a clear and structured manner. --- ### 🔹 Divisions of the Nose The nose is divided into: - **External Nose** – visible part of the nose - **Internal Nose** – includes right and left **nasal cavities**, separated by the **nasal septum** In this post, we'll focus on the **external nose**. --- ### 📐 Shape and Orientation - **Pyramidal in shape** - **Root**: Directed upwards - **Base**: Directed downwards --- ### 🧱 Layers of the External Nose 1. **Skin** 2. **Subcutaneous tissue** (with 4 sublayers) - Superficial fatty layer - Fibromuscular layer (SMAS) - Deep fatty layer - Periosteum and perichondrium 3. **Osteocartilaginous framework** **1️⃣ Skin Layer** - **Variable thickness** depending on skin type and anatomical location - **Thin and loose** over the **dorsum and sides** - **Thick and adherent** over the **tip and alar region**, containing numerous **sebaceous glands** >Can you name a disease where we see hypertrophy of the sebaceous glands on the nose? **2️⃣ Subcutaneous Tissue Layer** a. **Superficial Fatty Layer** - Lies directly beneath the dermis b. **Fibromuscular Layer (SMAS)** - Contains **muscles of facial expression** associated with nasal movements - All these muscles are supplied by the **facial nerve (CN VII)**. >What are the different muscles of the nose and what are their actions? >Which muscle is the ONLY dilator of the nose? c. **Deep Fatty Layer** - Contains **neurovascular structures** >What is the surgical importance of the deep fatty layer? d. **Periosteum and Perichondrium** - Covers underlying bone and cartilage **3️⃣ Osteocartilaginous Framework** Divided into: **🔸 Bony Part (Upper 1/3)** - Nasal bones(2) – fused in midline - Nasal process of frontal bone - Frontal process of maxilla **🔸 Cartilaginous Part (Lower 2/3)** 1. **Upper lateral cartilage** - Trapezoid shaped - Forms the **nasal valve (limen nasi)** intranasally 2. **Lower lateral cartilage (Alar cartilage)** - U-shaped - Has **lateral crus** (forms ala) and **medial crus** (runs in columella) 3. **Lesser alar (Sesamoid) cartilages** - Small cartilages above and lateral to alar cartilage 4. **Septal cartilage** - Forms anterior support to nasal dorsum >What deformity do you see on loss of septal cartilage? --- ### 🩸 Arterial Supply of External Nose | Artery | Branches and Area Supplied | | --- | --- | | Facial artery | Angular artery → Alar region
Superior labial artery → Columella & anterior septum | | Ophthalmic artery | Dorsal nasal artery → Dorsum and sidewall | | Anterior ethmoidal artery | External nasal branch → Nasal dorsum | | Infraorbital artery | Sidewall of the nose | --- ### 🩸 Venous Drainage of External Nose - **Does not parallel arteries** - Drains into **arteriovenous territories**: - **Frontomedian area** → Facial vein - **Orbitopalpebral area** → Ophthalmic vein >What is the **Danger Area of the Face**? Why is it called so? --- ### 🧠 Nerve Supply of External Nose | Nerve | Region Supplied | | --- | --- | | Supratrochlear & Infratrochlear (CN V1) | Root, bridge, upper sidewall | | Infraorbital (CN V2) | Lower sidewall | | External nasal (from anterior ethmoidal) | Dorsum and nasal tip | --- ### 🌿 Lymphatic Drainage of External Nose - **Submental nodes** - **Submandibular nodes** - **Facial nodes** - Occasionally, **parotid region** - Drainage is **often bilateral** --- ### 📚 Key Exam Points - **Osteocartilaginous framework** – common theory & viva question - **Danger area of the face** – high clinical relevance --- ## About This Note This free ENT note on Anatomy of the External 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/external-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 ## About The ENT Resident 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. Browse all ENT notes and lectures on The ENT Resident: https://www.theentresident.com/ent-notes-lectures.md ## Medical-use Boundary The ENT Resident provides educational material for medical learning and revision. It does not provide patient-specific medical advice, diagnosis, or emergency care, and it is not a substitute for evaluation by a qualified healthcare professional. ## More Resources - Learn about the Premium ENT Notes, preview a complete sample, and find purchase options: https://www.theentresident.com/premium.md - Premium note for this topic, Anatomy of the External Nose: https://theentresident.gumroad.com/l/zclmml - Buy Complete Notes on Anatomy of Nose: https://theentresident.gumroad.com/l/anatomyofnose - Read student testimonials: https://www.theentresident.com/testimonials.md - Contact The ENT Resident: https://www.theentresident.com/contact.md --- A complete index of all pages on this site, with descriptions and markdown links can be found here: https://www.theentresident.com/llms.txt