--- title: "Anatomy of Tonsil - Parts, Functions, Blood Supply, Nerve Supply, Applied Anatomy" description: "ENT notes on Anatomy of Tonsil - Parts, Functions, Blood Supply, Nerve Supply, Lymphatic Drainage, Applied Anatomy." source: "The ENT Resident" author: "Dr. Mausumi Das" canonical_url: "https://www.theentresident.com/ent-notes-lectures/tonsil-anatomy-function-parts" categories: ["Pharynx"] video: "https://www.youtube.com/watch?v=5xnVKFFpHyI" image: "https://media.theentresident.com/og-images/tonsil-anatomy-function-parts.png" --- # Anatomy of Tonsil - Parts, Functions, Blood Supply, Nerve Supply, Applied Anatomy ENT notes on Anatomy of Tonsil - Parts, Functions, Blood Supply, Nerve Supply, Lymphatic Drainage, Applied Anatomy. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=5xnVKFFpHyI ## ๐Ÿง  Anatomy of Tonsil The **Palatine tonsils** are paired lymphoid structures forming an important part of **Waldeyerโ€™s ring**. --- ### ๐Ÿ“ Location of the Tonsil - Tonsils are **two in number**, one on each side - Located on the **lateral wall of the oropharynx** - Lie in the **tonsillar fossa**, between **Anterior pillar** & **Posterior pillar**. - Covered laterally by a **tonsillar capsule** > Which muscles form the Anterior pillar and Posterior pillar of Tonsillar Fossa? --- ### ๐Ÿ“ Size & Shape of Tonsil #### ๐Ÿ”น Size (Age Related Changes) - Enlarges rapidly at **5-6 years** - Maximum size at **puberty** - Gradual involution after puberty - Minimal lymphoid tissue in old age #### ๐Ÿ”น Pathological Variation - **Acute tonsillitis** โ†’ enlarged tonsils - **Chronic tonsillitis** โ†’ shrunken, fibrotic tonsils #### ๐Ÿ”น Shape - **Ovoid mass** of lymphoid tissue - Long axis runs **superior โ†’ inferior** - Fixed anatomical position --- ### ๐Ÿงฉ Parts of the Tonsil Each tonsil has: - **Two poles** - Upper pole - Lower pole - **Two surfaces** - Medial surface - Lateral surface --- ### ๐Ÿ” Upper Pole of Tonsil - Extends into the **soft palate** - Covered by **semilunar fold** - Fold encloses a potential space: **Supratonsillar fossa** > What is the Clinical importance of the Upper Pole of Tonsil? --- ### ๐Ÿ”ป Lower Pole of Tonsil - Attached to the **tongue** - A triangular mucosal fold from anterior pillar encloses: **Anterior tonsillar space** - Separated from tongue by: **Tonsillolingual sulcus** > What is the Clinical importance of the Tonsillolingual sulcus? --- ### ๐Ÿ‘… Medial Surface of Tonsil 1- **Epithelium** > What is the Epithelial lining of the tonsil? 2- **Tonsillar Crypts** - Epithelium dips inward forming **12โ€“15 crypts** - One large crypt: **Crypta magna / intratonsillar cleft** > What does crypta magna represent embryologically? 3- **Secondary Crypts** - Branch from primary crypts - Can fill with: - Desquamated epithelium - Bacteria - Food debris --- ### ๐Ÿงฑ Lateral Surface & Capsule of Tonsil - Covered by **fibrous tonsillar capsule** - Between capsule & tonsillar bed lies: - **Loose areolar tissue** - **Paratonsillar vein** - This space is: - **Peritonsillar space** > What is the clinical importance of Peritonsillar space? --- ### ๐Ÿ›๏ธ Tonsillar Bed (Very Important Viva Topic) **๐Ÿ”น Structures (Medial โ†’ Lateral)** 1. Tonsillar capsule 2. Loose areolar tissue (paratonsillar vein) 3. Pharyngobasilar fascia 4. Superior constrictor muscle 5. Buccopharyngeal fascia 6. Styloglossus muscle 7. Glossopharyngeal nerve 8. Facial artery branches 9. Medial pterygoid muscle 10. Submandibular gland 11. Angle of mandible ๐Ÿ“Œ ***Must remember sequence for viva*** >๐Ÿ“˜ In my detailed notes, Iโ€™ve mentioned a mnemonic to remember the structures of Tonsil bed easily. --- ### ๐Ÿฉธ Blood Supply of Tonsil #### ๐Ÿ”ด Arterial Supply of Tonsil 1. **Tonsillar artery** โ€“ โญ Main supply 2. Ascending palatine artery 3. Ascending pharyngeal artery 4. Dorsal lingual branches 5. Descending palatine artery ๐Ÿ“Œ Tonsillar artery enters via **inferior pole** after piercing superior constrictor > What are the parent branches of each of the arteries supply the tonsil? #### ๐Ÿ”ต Venous Drainage of Tonsil - Via **pharyngeal venous plexus** - Key vein: - **Paratonsillar vein** - Also called **external palatine vein** > What is the applied importance of Paratonsillar vein? --- ### ๐Ÿงฌ Lymphatic Drainage of Tonsil - Lymphatics pierce **superior constrictor** - Drain into: **Upper deep cervical lymph nodes** - Most important node: **Jugulodigastric node** > How would you locate the Jugulodigastric node? --- ### ๐Ÿง  Nerve Supply of Tonsil - Via **tonsillar plexus** - Formed by: - Tonsillar branches of **glossopharyngeal nerve** - Fibers from **maxillary nerve** via lesser palatine nerve ๐Ÿ“Œ Important for **referred otalgia** --- ### ๐Ÿ›ก๏ธ Function of Tonsil - Part of **Waldeyerโ€™s ring** - Acts as **first line of defense** - Guards upper aerodigestive tract against: - Bacteria - Viruses - Other antigens (inhaled/ingested) > What is Waldeyerโ€™s ring? What are the different components of Waldeyerโ€™s ring? --- ### โš•๏ธ Applied Anatomy of Tonsil - Referred Otalgia > What is Referred Otalgia? What are the different nerves involved and causes of Referred Otalgia? - Peritonsillar Abscess (Quinsy) > What is Quinsy? How does a patient with Quinsy present? What is it's management? - Post Tonsillectomy Hemorrhage > Which structure involvement most commonly causes Post Tonsillectomy Hemorrhage? - Internal Carotid Artery Relation - Lies **2.5 cm posterolateral** to tonsil - Important during deep dissection --- ### ๐Ÿ“Œ Exam Pearls - Crypta magna โ†’ 2nd pharyngeal pouch - Jugulodigastric node โ†’ tonsillar lymph drainage - Paratonsillar vein โ†’ post-tonsillectomy bleed - Glossopharyngeal nerve โ†’ referred ear pain - Tonsillolingual sulcus โ†’ carcinoma risk --- ## About This Note This free ENT note on Anatomy of Tonsil - Parts, Functions, Blood Supply, Nerve Supply, Applied Anatomy was written by Dr. Mausumi Das and is paired with a corresponding video lecture. 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