larynx skeleton interior A&N supply1 & 2-1.pptx

larynx skeleton interior A&N supply. It's a hollow tube that's about 4 to 5 centimeters (cm) in length and width. It lets air pass from your throat (pharynx) to your trachea on the way to your lungs. Your larynx is also the reason you're able to make sounds, so it's often called your voice box. The larynx commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food

1. LARYNX

2. LARYNX

3. LARYNX Larynx is an organ of respiration and phonation. It protects the lower respiratory passage and act as a ‘watch dog’ to prevent entry of any materials other than air. As it is producing voice , it is also called voice box.

4. LOCATION: The larynx is situated in the anterior midline of the neck in front of laryngopharynx . It lies opposite to 3rd, 4th, 5th, and 6th cervical vertebrae in adult . EXTENTION : Superiorly – Upper border of epiglottis. Inferiorly - Lower border of cricoid cartilage

5. COMMUNICATIONS: Above : Laryngopharynx through inlet of larynx. Below : Trachea. SIZE: Length : Male - 44mm Female - 36mm.

6. SKELETON The skeletal framework of the larynx consists of 9 cartilages. CARTILAGES: 3 unpaired 3 paired. 1. Unpaired cartilages: (a) Thyroid (b) Cricoid (c) Epiglottis 2. Paired cartilages: (a) Arytenoid (b) Corniculate (c) Cuneiform

7. Thyroid cartilage It is the prominent cartilage of larynx and acts as a shield to protect the larynx from the front. It lies opposite the C 3 and C 4 vertebrae. Parts : - Two laminae - Right - Left Fearures of Lamina: It is quadrilateral in shape. 4 borders - Anterior , Posterior, Superior, Inferior. 2 surfaces - Outer and Inner.

8. Anterior border: Lower part of anterior borders meets to form Thyroid angle. The thyroid angle is prominent in males called laryngeal prominence or Adam’s apple. The angle measures about 90° in males and 120° in females. Upper part of anterior borders do not meet to form Thyroid notch .

9. Posterior border: It is free . It prolonged upwards as superior horns/ cornu and downwards as inferior horns/ cornu . It provides conjoined insertion to the following three muscles 1. Palatopharyngeus . 2. Salpingopharyngeus . 3. Stylopharyngeus . Superior border: It is convex infront and concave behind . Thyrohyoid membrane attached whole its length.

10. Inferior Border: It is straight in front and concave behind . In median plane it is connected to cricoid cartilage by conus elasticus ( cricothyroid ligament). Outer surface: It presents an oblique line which extent from the superior thyroid tubercle to the inferior thyroid tubercle. It provides attachment to the following three muscles. 1. Thyrohyoid . 2. Sternothyroid . 3. Inferior constrictor ( thyropharyngeus part only).

11. Inner surface It provides attachment to; 1.median thyroepiglottic ligament. 2.vestibular ligament. 3.vocal ligament. 4.thyroarytenoid muscle. 5.thyroepiglottic muscle. 6. vocalis muscle.

12. Cricoid cartilage It is a signet-shaped ring of cartilage. It consists of narrow anterior arch and a broad posterior lamina. The cricoid cartilage is situated at the level of C6 vertebra. It completely encircles the lumen of the larynx and considered as the foundation stone of the larynx.

13. Arytenoid cartilages Each cartilage is pyramidal shaped. It has an , Apex Base 3 surfaces –medial, anterolateral & posterior. 2 processes - vocal process, muscular process. Apex articulate with corniculate cartilage. Base is concave & articulate with the upper border of cricoid lamina. Base is prolonged anteriorly to form vocal process . Prolonged laterally to form muscular process.

14. Epiglottis Leaf shaped cartilage. Extends up behind the tongue and hyoid bone. Its upper end is broad and free. Its lower end ( stalk ) is narrow and connected to posterior surface of angle of thyroid cartilage by thyroepiglottic ligament. Anterior surface : connected to base of tongue by 3 folds (median & 2 lateral glossoepiglottic fold). connected to hyoid bone by hyoepiglottic ligament. Posterior surface of epiglottis presents a tubercle in its lower part. Right & left margin attached to arytenoid cartilage by aryepiglottic fold .

15. Corniculate cartilages: These are two small conical nodules, which articulate with the apices of the arytenoid cartilages. They lie in the posterior parts of the aryepiglottic folds. Cuneiform cartilages : They are tiny rod-shaped cartilages . They are lying just above the corniculate cartilages in the posterior parts of the aryepiglottic folds.

16. TYPES OF LARYNGEAL CARTILAGES HYALINE CARTILAGE Thyroid Cricoid Basal parts of arytenoid cartilages Hyaline cartilage tend to ossify after 25 years of age. ELASTIC CARTILAGE Epiglottis Corniculate Cuneiform Apex and vocal process of arytenoid cartilages

17. Laryngeal joints Cricothyroid joint Cricoarytenoid joint Arytenocorniculate joint Cricothyroid joint: It is a plane synovial joint between the inferior cornu of the thyroid cartilage and side of cricoid cartilage. It permits Rotatory movement around the transverse axis.

18. Cricoarytenoid joint: It is a synovial joint between the base of the arytenoid and the upper border of the lamina of cricoid cartilage. It permits 1. Rotatory movement around the vertical axis. 2. Gliding movements in all directions .

19. Arytenocorniculate joint: It is a synovial joint between the arytenoid and corniculate cartilages. It is of no functional significance.

20. LIGAMENTS AND MEMBRANES The skeletal framework of the larynx is interconnected by a number of ligaments and fibrous membranes. They are divided into 2 types: 1. Extrinsic 2. Intrinsic

21. EXTRINSIC LIGAMENTS Thyrohyoid membrane: It connects thyroid cartilage to hyoid bone. It median & lateral part thickens to form median & lateral thyrohyoid ligaments. Thyrohyoid membrane is pierced by internal laryngeal nerve & superior laryngeal vessels.

22. 2.Hyoepiglottic ligament : Connects upper end epiglottis to posterior aspects of hyoid bone. 3. Cricotracheal ligament : Connects cricoid cartilage with upper end of first tracheal ring.

23. INTRINSIC LIGAMENTS Broad sheet of fibroelastic membrane present outside to the mucous membrane of larynx. It is interrupted by sinus of larynx. The part above the sinus is called quadrate (quadrangular) membrane and part below the sinus is called cricovocal membrane or conus elasticus

24. 1.Quadrate membrane : Part above the sinus extends from arytenoid to epiglottis. Its upper border forms the aryepiglottic fold. Lower border thickened to form vestibular ligament. Vestibular ligament: Extends from posterior surface of thyroid cartilage to lateral surface of arytenoid cartilage.

25. Conus elasticus / cricovocal membrane: Part of fibroelastic membrane below the sinus . Its upper border is free and slightly thickened to form vocal ligament . Vocal ligament : It extends anteroposteriorly from posterior surface of the thyroid cartilage to the vocal process of arytenoids cartilage.

26. 3D MODELS

27. INTERIOR OF LARYNX or CAVITY of LARYNX Laryngeal cavity extends from laryngeal inlet to lower margin of cricoid cartilage. The anterior wall of laryngeal cavity is longer than the posterior wall.

28. Mucous folds of larynx Interior of larynx presents 3 pairs of mucous folds. Above downwards: Aryepiglottic folds Vestibular folds (false vocal cords) Vocal folds (true vocal cords)

29. Aryepiglottic folds: It is formed by upper free margin of quadrate membrane . It extends from arytenoid cartilage to epiglottis. Vestibular folds or false vocal cords: It is formed by vestibular ligament. It extends from posterior surface of thyroid cartilage to lateral surface of arytenoid cartilage. Vocal folds or true vocal cords: It is formed by vocal ligament and vocalis muscle. It extends from angle of thyroid cartilage to the vocal process of arytenoids cartilage.

30. SUBDIVISIONS OF THE LARYNGEAL CAVITY Vestibular fold & vocal fold divides the cavity of larynx into three parts, Vestibule – part above the vestibular fold. Ventricle – part b/w vestibular & vocal folds. Infraglottic part – part below the vocal fold.

31. Vestibule ( supraglottic part ) It extends from aryepiglottic folds to the vestibular folds. The space between the aryepiglottic folds forms the inlet of larynx. Inlet of larynx: It is an oblique opening. Boundaries : Anteriorly - upper end of epiglottis. On sides - aryepiglottic folds. Posteriorly - interarytenoid fold.

32. Ventricle or sinus of the larynx ( glottic part) It is a space b/w the vestibular folds & vocal folds . It is also called sinus of morgagni . Saccule of larynx ( oil can of larynx ) is the mucous diverticulum extends upwards blindly from the anterior part of the sinus on each side. Secretion of the mucous glands contained in the saccule lubricates the vocal folds.

33. The space between vestibular folds is called rima vestibuli . When the vestibular folds come together, they prevent the air from leaving the lungs, as when a person holds his breath. The space between the right and left vocal folds is called rima glottidis .

34. Rima glottidis It is the narrowest anteroposterior cleft of the laryngeal cavity in between the right and left vocal folds . Its shape is altered by the movements of vocal folds. Boundaries: In front: Angle of thyroid cartilage. Behind: Interarytenoid fold. On each side: Vocal fold in anterior 3/5 and arytenoid cartilage in posterior 2/5. Subdivisions of Rima Glottidis : 1. Intermembranous part in the anterior 3/5, between the vocal cords. 2. Intercartilaginous part in the posterior 2/5, between the arytenoid cartilage.

35. Movements of Vocal folds Abduction Adduction Tension Relaxation

36. SHAPE OF RIMA GLOTTIDIS During quiet respiration: Intermembranous part is triangular Intercartilaginous part is rectangular ( cords gently abducted). During forced inspiration : Vocal cords are fully abducted & rima assumes diamod shaped . High pitched sound : Rima reduced to a linear chink due to adduction to both intermembranous & intercartilaginous parts. In whispering voice : Intermembranous part is highly adducted and intercartilaginous remains widely open and look like inverted funnel shaped.

37. MUSCLES They are two types: extrinsic & intrinsic . Extrinsic muscles They are attach larynx to surrounding structures. 1.Palatopharyngeus 2.Salpingopharyngeus 3.Stylopharyngeus 4.Thyrohyoid 5.Sternothyroid All these are elevate the larynx except sternothyroid which depress the larynx.

38. ACTIONS Abduction of vocal cord – posterior cricoarytenoids. Adduction of vocalcord – lateral cricoarytenoids, transverse arytenoid , cricothyroids, thyroarytenoids. Tense the vocal cord – cricothyroids. Relax the vocal cord – thyroarytenoids , vocalis. Close the inlet of larynx – oblique arytenoids , aryepiglotticus. Open the inlet of larynx – thyroepiglotticus.

39. Cricothyroid The only muscle outside the larynx. It is called tuning fork of larynx. Origin: Lower border and lateral surface of cricoid . Insertion: Inferior cornua and lower border of thyroid cartilage. Action: Tension of vocal cords.

40. Posterior Cricoarytenoid It is a triangular muscle. It is called as safety muscles of larynx. . Origin: Posterior surface of the lamina of the cricoid cartilage. Insertion: Posterior aspect of muscular process of the arytenoid cartilage. Action: Abduction of vocal cords.

41. Lateral Cricoaryfenoid Origin: Lateral part of the upper border of the arch of the cricoid cartilage. Insertion: Anterior aspect of muscular process of the arytenoid cartilage. Action : Adduction of vocal cords.

42. Transverse Arytenoid This is the only unpaired intrinsic muscle of the larynx. Origin: Posterior surface of one arytenoid cartilage. Insertion : Posterior surface of opposite arytenoid cartilage. Action : Adduction of vocal cords.

43. Oblique Arytenoid Origin : Muscular process of one arytenoid cartilage . Insertion : Apex of opposite arytenoid cartilage. Action : Adduction of vocal cords.

44. Aryepiglotticus This is made up of some fibres of the oblique arytenoid which are continued into the aryepiglottic fold . Origin : Muscular process of arytenoid cartilage . Insertion : Margin of epiglottis. Action : Closing inlet of larynx.

45. Thyroarytenoid Origin: Posterior aspect of the angle of the thyroid cartilage. Insertion: Anterolateral surface of the arytenoid cartilage. Action : Relaxation of vocal cords.

46. Thyroepiglotticus Some of the upper fibres of the thyroarytenoid curve upwards into the aryepiglottic fold . Origin : Posterior aspect of angle of the thyroid cartilage. Insertion : Margin of epiglottis. Action : Opening inlet of larynx.

47. Vocalis muscle It is the detached medial part of the thyroarytenoid and lies within the vocal fold just lateral to the vocal ligament. Origin : It arises from the thyroid angle and anterior part of vocal ligament. Insertion : Lateral surface of the vocal process . Action : Tension of anterior part of vocal cord and relaxation of posterior part of vocal cord. The segmental tension of vocal ligament helps in the modulation of voice.

48. NERVE SUPPLY OF MUSCLES: All the muscles of larynx supplied by Recurrant laryngeal nerve except cricothyroid which is supplied by External laryngeal nerve .

49. Exceptions: Cricothyroid is the only muscle lying on the outer aspect of the larynx. All intrinsic muscle of larynx are paired except transverse arytenoid. All the intrinsic muscle of larynx are adduct the vocal cord except posterior cricoarytenoid.

50. Nerve supply of larynx: Sensory supply to mucous membrane: Secretomotor supply: Recurrent laryngeal nerve. Motor supply All the intrinsic muscles supplied by recurrent laryngeal nerve,except cricothyroid which is supplied by external laryngeal nerve . Above vocal folds Internal laryngeal nerve Below vocal folds Recurrent laryngeal nerve

51. BLOOD SUPPLY ARTERIAL SUPPLY VENOUS DRAINAGE Above vocal fold Superior laryngeal artery ( branch of superior thyroid artery) Superior laryngeal vein Superior thyroid vein Below vocal fold Inferior laryngeal artery (branch of inferior thyroid artery) Inferior laryngeal vein Inferior thyroid vein

52. LYMPHATIC DRAINAGE Above vocal cord Anterosuperior group of deep cervical nodes Below vocalcord Posteroinferior group of deep cervical nodes.

53. Clinical anatomy 1. When any foreign object enters the larynx severe protective coughing is excited to expel the object. However, damage to the internal laryngeal nerve produces anaesthesia of the mucous membrane in the supraglottic part of the larynx. 2. When only one recurrent laryngeal nerve is paralysed , the opposite vocal cord compensates for it and phonation is possible but there is hoarseness of voice. 3. When both recurrent laryngeal nerves are interrupted : The vocal cord lie in between adduction and abduction. Phonation is completely lost. Breathing is difficult.

54. 4. . When both recurrent laryngeal nerves and external laryngeal nerve interrupted, the vocal cord abducted and fixed due to paralysis of all intrinsic muscles. This is called Cadaveric position of vocal cords. 5. The larynx can be examined directly through an instrument called laryngoscope .

55. 6.Laryngitis : Infection of larynx results hoarseness of voice. 7. Laryngeal oedema : Results obstruction of breathing. 8. Vocal nodule ( singer’s / screamer’s nodules) Vocal nodule appear on the free edge of both cords at the junction of anterior 1/3 and posterior 2/3 ( the point of maximum vibration of cords).