SURGICAL ANATOMY OF LARYNX.pptx by Dr Laraib

Details of anatomy of larynx with surgical related importance of structures.

1. SURGICAL ANATOMY OF LARYNX Presented by : Dr. Laraib Abro. PGR ENT SZH LAHORE

2. INTRODUCTION : The LARYNX is an apparatus made up of cartilage, ligaments, muscles, and mucous membrane, which guards the entrance to the lower respiratory passages (trachea, bronchi, and lungs) and houses the vocal cords. It is also the organ of phonation.

3. The hyoid bone : Described with the larynx because of its anatomic association with the laryngeal apparatus. located in front of the 3rd cervical vertebra.

4. SURGICAL IMPORTANCE: In tracheal resection and anastomosis, a tension-free closure of the distal airway is essential. The larynx can be released and "dropped" from the hyoid bone to reduce tension on the distal suture line. This is accomplished by detaching the infrahyoid muscles from the inferior surface of the hyoid bone body and cutting the hyoid bone just lateral to the lesser cornua This releases the central body of the hyoid and larynx.

5. During the excision of a thyroglossal duct cyst, excising the entire tract along with the central body of the hyoid bone ( Sistrunk procedure) reduces the recurrence rate.

6. formed by 2 laminae which fuse ventrally in the midline of the neck, forming a protuberance, the laryngeal prominence or "Adams apple, The 2 laminae meet at an angle of 90° in the male and 120° in the female. The upper limit of fusion of the two laminae forms the superior thyroid notch

7. On the lateral, external surface of each thyroid lamina is-ridge ,called the oblique line Attaches to 3 muscle: Sternothyroid Thyrohyoid,and The thyropharyngeus

8. SURGICAL IMPORTANCE : The thyroid cartilage is divided in the midline to expose the endolarynx for various procedures (for example, partial laryngectomy , laryngotracheoplasty , and arytenoidectomy ). The vocalis muscle and vocal ligaments attach to the inner surface of the thyroid cartilage at the anterior commissure On the external laryngeal surface in adult males this point is halfway between the thyroid notch and the inferior border of the thyroid cartilage.It is slightly higher in adult females In many laryngo-fissure approaches, it may be beneficial to stay below the midpoint in order to avoid dividing the anterior commissure.

9. CRICOID CARTILAGE Shaped like a signet ring. Signet-shaped portion of the cricoid faces posteriorly The arch is located anteriorly, The cricoid cartilage is situated at vertebral level C6 (occasionally reaching the middle of C6), just below the thyroid

10. The cricoid lamina has 2 superior facets- articulate with the arytenoid cartilages and attach to them by the ligaments cricoarytenoid 2 lower lateral facets of the lamina articulate with the inferior horns of the thyroid cartilage. The lower border of the cricoid cartilage is joined to the first tracheal ring by means of the thick cricotracheal ligament.

11. SURGICAL IMPORTANCE Injury to the cricoid cartilage from intubation or trauma may result in perichondritis and lead to subglottic stenosis. Surgical approaches to repair long-standing subglottic stenosis involve the expansion of the circumference of the cricoid ring with autologous cartilage grafts. Tracheotomies are usually performed at least one tracheal ring below the cricoid cartilage (2nd or 3rd tracheal ring) to avoid subglottic stenosis During an emergency cricothyroidotomy , the tracheostomy tube is inserted through the median cricothyroid ligament - the quickest and easiest access to the airway. To avoid permanent laryngeal stenosis — cricothyroidotomy must be converted to a standard tracheotomy within days.

12. ARYTENOID CARTILAGES: Almost pyramidal in shape with 3 surfaces,a base, and an apex. Base has 2 processes: Anteromedially directed vocal process - vocal ligament is attached Short, broad, laterally projecting Muscular process - lateral and posterior cricoarytenoid muscles are attached

13. SURGICAL IMPORTANCE Cricoarytenoid fixation may occur from arthritis or perichondritis (intubation injury) and limit vocal fold mobility.  Arytenoidectomy through an external or endoscopic approach may alleviate arytenoid fixation or paralysis. Submucosal Arytenoidectomy encoctomy which preserves an intact laryngeal mucosa.

14. CORNICULATE CARTILAGES OF SANTORINI small fibroelastic nodules that sit on the apices of arytenoids It has little functional importance in humans. CUNEIFORM CARTILAGE OF WRISBERG Rod shaped. situated in aryepiglottic fold anterior to the corniculate cartilage. May be entirely absent.

15. an occasional minute nodule. located in the posterior margin of the thyrohyoid membrane.

16. EPIGLOTTIS Oblong leaf shaped Located behind the root of the tongue and the body of the hyoid bone and in front of the laryngeal entrance. It has: 2 ends- upper & Lower 2 surfaces- Anterior &Posterior 2 Lateral borders

17. SURGICAL IMPORTANCE Acute epiglottitis , may cause airway obstruction in children To rule out foreign bodies, a lateral x-ray may be ordered if the general condition of the child permits. Laryngeal visualization must be done in the operating room to avoid airway occlusion, aspiration, and cardiac arrest. Intubation and tracheostomy are the procedures

18. MEMBRANES AND LIGAMENTS OF LARYNX Extrinsic membranes: - Thyrohyoid & Cricotracheal membrane Intrinsic membranes : - Quadrangular membrane & Conus elasticus Ligaments & Folds : Epiglottic ligaments Aryepiglottic fold Vestibular ligament or False vocal cords Vocal ligaments

19. THYROHYOID MEMBRANE provides an extensive connection between the thyroid cartilage and the hyoid bone bilaterally and anteriorly. Thickens anteriorly forming median thyrohyoid ligament & posteriorly forming lateral thyrohyoid ligament.

20. SURGICAL IMPORTANCE The superior laryngeal neurovascular bundle may be injured by surgical approaches to the pharynx One must observe great care when dissecting the greater cornu of the hyoid bone and the superior horn of the thyroid cartilage during various pharyngotomy approaches

21. connects the most superior tracheal cartilage with the inferior border of the cricoid cartilage

22. CONUS ELASTICUS / CRICOTHYROID MEMBRANE Conus Elasticus connects the cricoid cartilage with the thyroidand arytenoid cartilages composed of dense fibroconnective tissue withabundant elastic fibers. Having 2 parts .Medial cricothyroid ligament Lateral cricothyroid ligament

23. SURGICAL IMPORTANCE - CRICOTHYROTOMY

24. LIGAMENTS & FOLDS OF LARYNX

25. EPIGLOTTIC LIGAMENTS/FOLDS Hyoepiglottic ligament Thyroepiglottic ligament Median glossoepiglottic Lateral glossoepiglottic or pharyngoepiglottic fold, attached between the base of the epiglottic cartilage and the pharyngeal wall at the root of the tongue

26. one on each side, contain the aryepiglottic muscles. associated with the superior border of the Quadrangular membrane. Both aryepiglottic folds constrict the entrance to the larynx and protect the respiratory pathway by not permitting food, liquids, and foreign bodies to enter the larynx and trachea.

27. VESTIBULAR FOLDS OR FALSE VOCAL CORDS Formed by the inferior edge of the quadrangular membrane. Attached in front to the thyroid cartilage below the attachment of epiglottis Overlap true vocal cords prior to cough or sneeze reinforcing the resistance against expiratory pressures

28. VOCAL CORDS The thickened, ligamentous, upper edges of the elastic tissue of the conus are the vocal ligaments or vocal cords.

29. Vocalis muscle is infact a portion of thyroarytenoid muscle At the anterior most portion of the vocal fold a mass of collagenous tissue is present--known as the anterior commissure tendon or Broyle's ligament. Lacking a submucosa and blood vessels, the vocal ligaments appear to be pearly white and shiny. The space between the true vocal cords (the intermembranous space) is known as the rima glottidis

30. LARYNGEAL INLET

31. Subdivided into 2 parts, 2/5 - intercartilaginous part (respiratory glottis,or interarytenoid space), between the arytenoid cartilages and 3/5 - the intermembranous part or glottis vocalis .

32. SURGICAL CONSIDERATION The epithelium of the true vocal cords does not have lymphatics. Therefore, metastatic disease is a rare phenomenon. The vocal folds are devoid of lymphatics, and it infact clearly forms the watershed zone between the upper and the lower group of lymphatics. The pathway of metastasis of glottic cancer is via the Delphian node or paratracheal nodes and finally nodes of the superior mediastinum.

33. LARYNGEAL MUCOSA Is mostly of the respiratory type called ciliated columnar epithelium , certain areas of the larynx covered with stratified squamous epithelium are :- upper area of the anterior, dorsal epiglottic surfaces, the ventral half of the aryepiglottic folds, and the vocal cords.

34. LARYNGEAL MUSCLES Extrinsic muscles - which move the entire larynx, Intrinsic muscles - which move the vocal cords.

35. EXTRINSIC MUSCLES OF LARYNX : ELEVATORS OF THE LARYNX The Suprahyoid Muscles : - Digastric , Stylohyoid , Mylohyoid , Geniohyoid Longitudinal Muscles of the pharynx : - Stylopharyngeus , Salpingopharyngeus , Palatopharyngeus DEPRESSORS OF THE LARYNX The Infrahyoid Muscles : - Sternohyoid , Sternothyroid , Omohyoid

36. INTRINSIC MUSCLES

37. LARYNGEAL JOINTS

38. LARYNGEAL SPACES : INTERNAL SPACES Vestibule Ventricles Subglottic or Infraglottic space EXTERNAL SPACES Pre-epiglottic space of Boyer Paraglottic space

39. VESTIBULE: pyramid-shaped space extends from the laryngeal inlet or aditus to the vestibular folds. VENTRICLE(sinus of larynx): It is a deep space between vestibular & vocal folds. The saccule is a diverticulum of mucous membrane extending from anterior end of ventricle

40. SURGICAL IMPORTANCE: Enlargement of the laryngeal saccule is often referred to as a laryngocele . Any obstruction of the laryngeal ventricle, such as a ventricular carcinoma, may lead to the formation of a laryngocele . A laryngocele may bulge through the aryepiglottic fold and obstruct the endolarynx (internal laryngocele ). It may be present outside of the thyrohyoid membrane ( external laryngocele )

41. 3. INFRAGLOTTIC OR SUBGLOTTIC SPACE: Th e distal part of the laryngeal cavity. E xtends from the glottis to the inferior border of the cricoid cartilage. The subglottic space begins below the curve formed by the vocal fold to the lower end of cricoid cartilage SURGICAL IMPORTANC E : Narrowest area in intants , so edema obstruction & respiratory distress occur early

42. External laryngeal spaces: Supraglottic laryngeal area is subdivided into laryngeal spaces Paired Lateral Paraglottic Spaces One midline Pre-Epiglottic Space

43. PARAGLOTTIC SPACE (TUCKERS SPACE): Bounded laterally by the thyroid cartilage, inferomedially by the conus elasticus, medially by the ventricle and the Quadrangular Membranes

44. PRE EPIGLOTTIC SPACE ( Boayers space) Bounded superiorly by the hyoepiglottic ligament, anteriorly by the thyrohyoid membrane and ligament, and Posteroinferiorly by the epiglottis and thyroepiglottic ligament. The pre-epiglottic space forms an inverted pyramid. continuous with the superior portion of the paraglottic space. contains abundant fat, blood vessels, lymphatics & mucosa glands.

45. SURGICAL IMPORTANCE: Epiglottic ( supraglottic ) carcinoma may spread through perforations in the epiglottis into the pre-epiglottic space. Since the pre-epiglottic space communicates laterally with the paraglottic spaces, a carcinoma is free to spread beyond the internal boundaries of the larynx. Therefore, supraglottic laryngectomy may be contraindicated.

46. REINKE’S SPACE Under the epithelium of vocal cords is a potential space with scanty connective tissue. Edema of this space causes fusiform swelling of membranous cords (Reinke’s Edema).

47. BLOOD SUPPLY OF LARYNX ARTERIAL :

48. VENOUS DRAINAGE: Upper Larynx Superior laryngeal vein Superior thyroid vein Internal jugular vein 2. Lower Larynx Inferior laryngeal vein Inferior thyroid vein subclavian vein

49. LYMPHATIC DRAINAGE : SUPRA GLOTTIC AREA: superior lymphatics drain to the upper deep cervical nodes, located at the level of the carotid bifurcation INFRA GLOTTIC AREA: drain to the pretracheal lymph nodes of the proximal trachea anteriorly, paratracheal nodes laterally and then to the deep cervical and superior mediastinal nodes.

50. GLOTIC AREA (VOCAL FOLDS) is relatively devoid of lymphatics. The space deep to the thin mucosa of the true vocal cords, which is called Reanke's space, has no direct lymphatic drainage. The spread of carcinoma is, likewise and fortunately, retarded until an invasive process involves tissue peripheral to the true vocal cord. DELPHIAN NODE : a midline prelaryngeal lymph node, adjacent to the thyroid gland, enlargement of which is indicative of metastasis from thyroid or laryngeal carcinoma.

51. Elective dissection of node levels II to IV for N-O laryngeal and hypopharyngeal carcinoma, Bilateral selective dissection is justified by the prevalence of bilateral metastases in midline and bilateral tumors. The superior neurovascular bundle may be injured during anterior and lateral pharyngotomy approaches to the larynx. Branches of the cricothyroid artery may be accidentally injured during emergency cricothyroidotomy .

52. Nerve supply of the larynx 1. Motor supply of the laryngeal muscles: All laryngeal muscles are supplied by the recurrent laryngeal nerves except cricothyroid muscle.  Cricothyroid muscle is supplied by the external laryngeal nerve 2. Sensory supply : Above the vocal cords- internal laryngeal nerve Below the vocal cords - reccurent laryngeal nerve