ANATOMY OF LARYNX & TRACHEOBRONCHIAL TREE BRIG MUHAMMAD ASHFAQ MBBS,FCPS,OJT(UK) ADVISOR ENT The Larynx • The larynx is a 5-7 cm long structure. • Its upper boundary starts at the tip of the epiglottis, opposite the 3rd to 4th, cervical vertebra. • Its lower end is at the lower border of the cricoid cartilage. • This lies opposite the 6th cervical vertebra. 2 LARYNX OUTLINE I. CARTILAGES II. LIGAMENTS III. MUSCLES IV. TERMS/AREAS V. INNERVATION VI. BLOOD SUPPLY VII. LYMPHATICS VIII. OBSTRUCTION OF LARYNX Cartilages connected by membranes and ligaments, moved by muscles Functions: 1) Sound production 2) Closure of Respiratory System - allows increase in Abdominal Pressure I. LARYNX: CARTILAGES A. THYROID CARTILAGE – Shield shaped - has Sup. & Inf. Horns from upper & lower edges LaryngealProminence Sup. Horns - Inf. horns make synovial hinges joint with Cricoid Cartilage; - Laryngeal Prominence = Adam’s Apple, more prominent in males LARYNX: CARTILAGES B. CRICOID complete ring of cartilage has narrow Arch ant., Lamina of broad Lamina post. cricoid Lamina of cricoid Arch of cricoid LARYNX: CARTILAGES C. Arytenoid – 2 pyramidal shaped cartilages above lamina – have synovial joints with Cricoid permit Swivel = Rotate Sliding = Ab/Adduct D. Corniculate - nodules above arytenoids in aryepiglottic folds E. Cuneiform – rod shaped, above corniculate cartilages LARYNX: CARTILAGES F. EPIGLOTTIS -leaf shaped cartilage posterior to root of tongue - connected to body of hyoid and post side of thyroid cartilage II. LIGAMENTS OF LARYNX 1. Thyrohyoid Membrane links Median larynx to hyoid;Median Thyrohyoid Thyrohyoid Ligament – Ligament thickened midline part 2. Cricothyroid Membrane links thyroid to cricoid; Median Median Cricothyroid Ligament – Cricothyroid thickened midline part Ligament 3. Cricotracheal ligament links Cricoid to first tracheal cartilage The Larynx: Anatomy The thyrohyoid membrane forms a C-shaped barrier around the anterior and lateral walls of the supraglottis, and inferiorly becomes confluent with the connective tissue in the perichondrium of the tracheal cartilaginous rings. 10 STRUCTURAL LIGAMENTS 4. Quadrangular Membrane links Arytenoid To epiglottis STRUCTURAL LIGAMENTS Aryepiglottic Folds – overlie Quadrangular membrane Arytenoid cartilage STRUCTURAL LIGAMENTS Lower free edge of Quadrangular membrane is Called Vestibular Ligament; deep to Vestibular (False Vocal) Folds B. FUNCTIONAL LIGAMENTS Conus Elasticus - Vibrating lips that arise from entire upper edge of arch of cricoid Attach: ant. to Thyroid, post. to Vocal Ligaments - Arytenoid Upper free Edges Deep to Vocal Folds Rima Glottidis - Opening Between Vocal ligaments The Larynx: Anatomy The vocal ligaments, are attached posteriorly to the apex of the arytenoids and corniculates. The cuneiforms extend laterally, between the layers of the vocal cords, from the anterior aspect of the arytenocorniculate complex. The epiglottis is attached to the base of the tongue by a median and two lateral glossoepiglottic folds. 15 B. FUNCTIONAL LIGAMENTS (In Coronal Section) Conus Elasticus Functions 1) Sound Production – Vibrate like lips of trumpet player; 2) Close Rima Glottidis stops outflow air, upward movement of diaphragm - when contract abdominal muscle pressure increases in abdominal cavity; occurs in childbirth, defecation Laryngoscopic view of Larynx Posterior Commissure Superior surface anatomy: True Vocal Cords Ventricle False Vocal Cords Anterior Aryepiglottic Commissure Fold III. MUSCLES OF LARYNX A. Extrinsic muscles (ex. hyoid muscles) - Move whole larynx as in swallowing B. Intrinsic Muscles 1) change tension in vocal lig ..changes pitch:- increase tension raises pitch, - decreased tension lowers pitch 1) CRICOTHYROID M. - 2) open & close Rima Tenses Glottidis Vocal Ligament Increasing Pitch III. MUSCLES OF LARYNX 2)THYROARYTENOID MUSCLE - Relaxes Vocal Ligaments Decreases pitch III. MUSCLES OF LARYNX 5) ARYTENOID (Transverse and oblique arytenoid) - Adduct vocal folds 4) LATERAL CRICOARYTENOID - Adduct vocal folds 3) POSTERIOR CRICOARYTENOID – Abducts vocal fold III. MUSCLES OF LARYNX 5) ARYEPIGLOTTIC MUSCLE Pulls epiglottis down During swallowing -Covers inlet to larynx - Not necessary in adult humans TERMS ASSOCIATED WITH LARYNX VESTIBULE - inlet above false vocal folds VESTIBULAR (FALSE VOCAL) FOLDS - overlie vestibular Ligaments VENTRICLE - area between true and false vocal folds; lateral extension is Laryngeal Sinus VOCAL (TRUE VOCAL) FOLDS - overlie vocal ligaments The Larynx Pyriform Sinus Superior surface anatomy: VALLECULAE -depressions (2) Between Med & Lat Glossoepiglottic Folds -Food/objects Lodge in Valleculae Epiglottis Vallecula Laryngoscopic view of Larynx Posterior Commissure Superior surface anatomy: True Vocal Major Landmarks Cords Ventricle False Vocal Cords Anterior Aryepiglottic Commissure Fold The Larynx Posterior Wall Of Hypopharynx Superior surface anatomy: Major Landmarks Corniculate Tubercle on Arytenoid Cartilage Cuneiform Tubercle Aryepiglottic Fold The Larynx Arytenoid Cartilage Superior surface anatomy: Major Landmarks True Vocal Cords Ventricle False Vocal Cords The Larynx Cartilaginous Rings of Trachea Superior surface anatomy: Major Landmarks to look for Vocal Cord Sulcus (on True Vocal Cords) False Vocal Cords Cricoid True Ring Vocal Cords QUIZ……This is the.. A. The epiglottis B. The ventricle C. The arytenoid cartilage D. The true vocal cord E. The false vocal cord Click for correct answer: B V. NERVES OF LARYNX – Branches of Vagus A. Superior Laryngeal N. divides to 1. Internal Laryngeal N. -GVA Sensory to Larynx Above True Vocal Folds 2. External Laryngeal N. -SVE Motor to Cricothyroid B. Recurrent Laryngeal N. - GVA Sensory to Larynx Below True Vocal Folds - SVE motor to all other Muscles of Larynx Blood supply Arterial sup. laryngeal artery inf. Laryngeal artery Venous sup. & inf. Thyroid veins VII. LARYNX - LYMPHATICS Superior Deep Cervical Nodes -Larynx above true vocal folds Inferior Deep Cervical Nodes- Larynx below true vocal folds Laryngeal function: Airway Protection The glottis: open for inspiration and closed for swallowing Open Closed 34 Laryngeal function: Phonation The vocal cords: Adducted for phonation; abducted for inspiration Adducted: Talking Abducted: Breathing 35 Laryngeal function: Phonation The vocal cords open and close while talking 36 TRACHEOBRONCHIAL TREE ANATOMY Tracheobronchial Tree Two Divisions Cartilaginous Airways – Primarily conducting airways; no gas exchange. Noncartilaginous Airways – Both conducting airways and sites of gas exchange. Dichotomous Branching Each airway divides into two “daughter” branches Each division (bifurcation) gives rise to a new generation of airways As airways divide, they become Shorter Narrower More numerous Cartilaginous Airways Trachea Main Stem Bronchi Lobar Bronchi Segmental Bronchi Subsegmental Bronchi TRACHEA Generation 0 11 – 13 cm long and 1.5 – 2.5 cm wide. Extends from Cricoid cartilage (6th cervical vertebrae) to the 2nd costal cartilage or 5th thoracic vertebrae. C6 – T5 15 - 20 C-shaped cartilages supports the trachea. Posterior wall is contiguous with esophagus TRACHEA The end of the trachea is called the carina. This is the division of the trachea into the right and left mainstem bronchi. Air is 100% saturated with water vapor and is . warmed to 37 °C (body temperature). The carina is located at approximately T5 or the Angle of Louis. The surgical opening into the trachea is called a tracheostomy. 2nd or 3rd tracheal ring. Main Stem Bronchi Generation 1 Trachea divides into the right and left mainstem bronchi – one for each lung Right Mainstem is wider, shorter and more vertical Branches at a 25 degree angle Left Mainstem Branches at a 40 – 60 angle Infants Both mainstem bronchi form a 55 angle with the trachea Lobar Bronchi Generation 2 Lobar Bronchi correlate to the number of lobes of the lung. The right mainstem bronchi will divide into the right upper, right middle and right lower lobe bronchi. The left mainstem bronchi will divide into the left upper and left lower lobe bronchi. Segmental Bronchi Generation 3 Correlate with the segments of the lung. There are 10 segmental bronchi on the right. There are 8 segmental bronchi on the left. Subsegmental Bronchi 4th to 9th Generations 1 to 4 mm in diameter Connective tissue containing: -Nerves -Lymphatics -Bronchial Arteries Non-Cartilaginous Airways Bronchioles 10th to 15th Generation. 1 mm in diameter. Simple cuboidal epithelium. No cartilage. Terminal Bronchioles Less than 0.5 mm in diameter. No cartilage (lack of support). Cilia and mucous glands disappear. Clara Cells appear Inter-bronchiole connections called Canals of Lambert begin to appear. Blood Supply to the Tracheobronchial Tree Bronchial Blood Supply Bronchial arteries nourish the tracheobronchial tree The arteries arise from the aorta and follow the tracheobronchial tree as far as the terminal bronchioles. Beyond the terminal bronchioles pulmonary arteries & capillaries feed the airways & alveoli. Normal bronchial blood flow is approximately 1% of the cardiac output. Also feed the mediastinal lymph nodes, pulmonary nerves, part of the esophagus and the visceral pleura QUESTIONS ?