--- title: "Muscles of Larynx" description: "A guide to the Muscles of Larynx for medical students and ENT residents." source: "The ENT Resident" canonical_url: "https://www.theentresident.com/ent-notes-lectures/muscles-of-larynx" categories: ["Larynx and Trachea"] video: "https://www.youtube.com/watch?v=ahrTbcc-aPA" image: "https://media.theentresident.com/og-images/muscles-of-larynx.png" --- # Muscles of Larynx A guide to the Muscles of Larynx for medical students and ENT residents. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=ahrTbcc-aPA ## 🧠 Muscles of the Larynx The muscles of the larynx are divided into two groups: - **Extrinsic muscles** - **Intrinsic muscles** ### 🔹 Extrinsic Muscles of Larynx These connect the larynx to surrounding structures and **maintain its position** in the neck. #### 🧭 Classification of Extrinsic Muscles: - **Suprahyoid muscles** – above the hyoid bone - **Infrahyoid muscles** – below the hyoid bone **🛠️ Functionally:** - **Suprahyoid muscles** → Elevate the larynx - **Infrahyoid muscles** → Depress the larynx During **swallowing**, these groups work in coordination: - When suprahyoids **contract** and infrahyoids **relax** → **larynx elevates** - Laryngeal descent: Suprahyoids simply **relax** → elastic recoil brings it down #### 🔸 **Infrahyoid Muscles (Depressors of Larynx)**: - Thyrohyoid - Sternothyroid - Sternohyoid #### 🔸 **Suprahyoid Muscles (Elevators of Larynx)**: ⬆️ **Primary Elevators** (direct attachment to thyroid cartilage): - Stylopharyngeus - Palatopharyngeus - Salpingopharyngeus ⬆️ **Secondary Elevators** (indirect elevation via hyoid bone): - Mylohyoid - Geniohyoid - Stylohyoid - Digastric --- ### 🔹 Intrinsic Muscles of Larynx These attach **one laryngeal cartilage to another**. **🎯 Functions:** - Coordinate **movement of laryngeal cartilages** - Control **shape, position, elasticity, and viscosity** of vocal folds - Move arytenoids at **cricoarytenoid joint** – opening and closing the glottis #### 🔸 Classification of Intrinsic Muscles 1️⃣ **Muscles Acting on the Vocal Cords** 🟢 **Abductor – Opens vocal cords** - **Posterior cricoarytenoid** - *Only abductor in the larynx* - **Origin**: Posterior cricoid lamina - **Insertion**: Muscular process of arytenoid - **Effect**: Abducts and elongates vocal folds; edges become rounded and passively stiff 🔴 **Adductors – Close vocal cords** - **Lateral cricoarytenoid** - **Origin**: Upper border of cricoid arch - **Insertion**: Muscular process of arytenoid - **Action**: Adducts and lowers vocal folds; sharpens edges - **Transverse arytenoid** - *Unpaired muscle* - Spans between both arytenoid cartilages - **Action**: Adducts vocal folds with little change to stiffness - **Oblique arytenoid** - Crosses from one arytenoid apex to the other - **Action**: Assists adduction; no major effect on fold stiffness --- 2️⃣ **Muscles Controlling Tension of Vocal Folds** - **Thyroarytenoid (including Vocalis)** - Lies **lateral and above** vocal ligament - **Vocalis**: thickened lower part - **Origin**: Posterior thyroid prominence - **Insertion**: Vocal process and anterolateral arytenoid - **Action**: Lowers, shortens, and thickens the folds; stiffens them actively - **Cricothyroid** - *Only intrinsic muscle outside the laryngeal cartilaginous framework* - **Origin**: Lateral cricoid arch - **Insertion**: Lower border and inferior horn of thyroid cartilage - **Action**: Tenses vocal folds by increasing distance between thyroid angle and arytenoids --- 3️⃣ **Muscles Acting on the Laryngeal Inlet** **🔓 Opener:** - **Thyroepiglottic** (part of thyroarytenoid) – widens inlet **🔒 Closers:** - **Oblique arytenoid** - **Aryepiglottic muscle** (continuation of oblique arytenoid) - Together, they **narrow the laryngeal inlet** during swallowing --- ## About This Note This note on Muscles of Larynx is one of the free ENT study notes published by The ENT Resident. It is free to read on the website, and it is paired with a full video lecture on YouTube. This note is categorized under [Larynx and Trachea](https://www.theentresident.com/ent-notes-lectures/category/larynx-and-trachea.md). The category page lists all the free ENT notes on that topic. Canonical page of this note: https://www.theentresident.com/ent-notes-lectures/muscles-of-larynx When citing or referencing this content, please credit The ENT Resident and link to the canonical page above. ## About The ENT Resident The ENT Resident is a free library of ENT notes and video lectures created by Dr. Mausumi Das (MS ENT), the ENT doctor and educator behind The ENT Resident YouTube channel (https://www.youtube.com/c/TheENTResident). These notes are written for ENT residents, ENT postgraduates preparing for exams, and MBBS students, to help them learn ENT clearly and score well. 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