Anatomy of the larynx by arijit


Published on

Anatomy of Larynx

Published in: Health & Medicine
1 Comment
No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide
  • Location: C4-C6
    Upper portion of larynx, which is continuous w/pharynx is almost triangular in shape
    Lower portion leading to trachea presents a circular appearance
  • This cartilage has two alae/wing which meet anteriorly, they form a depression called the THYROID NOTCH before meeting at the protruberance of the Adam’s apple or laryngeal prominence. Posteriorly, each wing has a superior cornu (extending upward about 2 cm) and inferior cornu (articulates w/cricoid cartilage below; ONLY DIRECT ARTICULATION, all others being maintained by muscles or ligaments)
    Ossifies at 20-30 years of age, begins in the inferior margin and progress cranially
  • Ossifies after the thyroid cartilage, first part to be calcified being the superior portion (w/c can be mistaken for a foreign body) Calcification progresses caudally.
    Lamina – flat portion of the ring llocated posteriorly and extends upward to form the POSTERIOR border of the larynx
    Only complete annular support of the laryngeal skeleton; preservation essential to maintain the enclosed airways.
    Level: Adult: C6-C7 Children: C3-C4
    Posterolaterally, cricoid articulates w/ Inferior cornu of the thyroid cartilage, which forms true synovial joints (permit a ROCKING action of the cricoid cartilage on the thyroid cartilage and a slight anteroposterior SLIDING motion (cricoid cart. Supports the 2 arytenoid cartilages on posterosuperior aspect)
  • Attached to the INSIDE of the thyroid cart. Anteriorly and projects upward and backward above the laryngeal opening.
    Petiole – small narrow portion of the glottis that is attached to the thyroid cart.
    The epiglottis is attached to the hyoid bone by the hyoepiglottic ligament.
    To the posterior part of the tongue by the median glossoepiglottic fold.
    To the sides of the pharynx by the lateral glossoepiglottic folds.
    To the thyroid cartilage by the thyroepiglottic ligament.
    The mucous membrane covering the epiglottis is reflected to the posterior part of the tongue as one medial and two lateral glossoepiglottic folds. Between these folds are depressions called epiglottic valleculae.
  • Calcify at the 3rd decade (Hyoid – ossifies fr. 6 centers shortly after brith, complete by 2 years of age)
    Arytenoids rest on the upper edge of the cricoid lamina at the posterior border of the larynx
  • Mobile end of VC – posterior
    Lateral promincence of each arytenoid cart. Is known as Muscular process, becoz of insertion site of numerous muscles
    Articulation of arytenoids with cricoid cart. Is at the CRICOARYTENOID JOINT, w/c permits a WIDE range of motion in 3 directions
  • When calcified, it can be mistaken as a foreign body in soft tissue Xray films
  • Thyrohyoid m&L –attach thyroid cart. To hyoid bone
  • Obvious from its name, the CT m&L connect the thyroid and cricoid cart.
    Cricothyrotomy – little fear of bleeding; however becoz of proximity to the vocal cords, this space shld not be used for prolonged intubation, as scar tissue may be produced.
  • Elastic m.-lies beneath the laryngeal mucosa, Fibrous framework of the larynx
    Ventricle of the larynx (ventricle of Morgagni)
    Quad membrane - Boundaries: extending from LATERAL margin of epiglottis to arytenoid and corniculate cart., and INFERIORLY to the false cord.
  • Median cricothyroid ligament – thickened anteior part of conus elasticus
    Vocal Ligament – is d free upper edge of the conus elasticus (strongest part), forms the framework of the vocal cord
    Thyroepiglottic ligament – ataches epiglottis to the thyroid cartilage
  • Divided into 3 parts by 2 folds of mucous membrane, namely the true and false cords.
    Vestibule – lies bet. Inlet and edges of false cords
    Ventricle (Morgagni) - Deep, spindle-shaped recess bet. True and false cords, lined by a mucous membrane that is covered externally by thyroarytenoid muscle
    Subglottic space – lies bet. True VC and lower border of cricoid cartilage
  • Saccule – conical pouch that ascends fr anterior part of the ventricle, lies bet. Inner surface of thyroid cartilage and false cord; has numerous mucous glands open into the surface of its lining mucosa for lubricating the vocal cords.
    Glottis – space bet. Free margin of the true VC, opening/aperture
    Posterior glottic chink in adult: 18-19mm; New born: 4mm; total glottic chink in a newborn: 14mm2
  • False cords – upper set of two horizontal folds on each side of the laryngeal cavity.
    TVC – covering epith. Is closely bound down to underlying vocal ligament, blood supplu here is poor hence the pearly white appearance of the vocal cords in life.
  • Intrinsic muscles, all are paired except Interarytenoid m.
    Larynx moves up during swallowing, down after.
    The extrinsic muscles move the larynx as a whole. The infrahyoid muscles or straps (omohyoid, sternohyoid, and sternothyroid) are depressors of the hyoid bone and the larynx, whereas the suprahyoid muscles (stylohyoid, digastric, mylohyoid and geniohyoid) and the stylopharyngeus are elevator of the hyoid bone and larynx.
  • Sternothyroid Muscle - a thin muscle located deep to the sternohyoid muscle, and is shorter and wider than it.
    Inferior attachment: posterior surface of manubrium of sternum.
    Superior attachment: oblique line of thyroid cartilage.
    Innervation: C2 and C3 by a branch of the ansa cervicalis.
    It depresses the hyoid bone and larynx after it has been elevated by muscles during swallowing and vocal movements.
    It also pulls the thyroid cartilage away from the hyoid bone, thereby opening the laryngeal orifice.
  • Muscles controlling Movements of the Vocal Cords
    ELN –ext laryngeal branch from SLN(CN X)
    ILN –inferior laryngeal nerve from RLN (CN X)
  • Muscles controlling the laryngeal inlet
  • Margins of aryepiglottic folds – none on he free edges of the vocal cords
    Reinke’s layer of connective tissue – lies immediately under the epith. Of larynx and superficial to elastic layer. NO GLANDS BENEATH AND NO LYMPH VESSELS IN IT.
  • RLN – longer course on L than R, L: turns around arch of aorta, R: around subclavian artery
    Nucleus ambiguus – somatic motor nucleus of CN IX, X, XI
    - supplied by PICA (fr. Veterbal a.) and AICA (fr. Basilar artery)
  • Anatomy of the larynx by arijit

    1. 1. STRUCTURE OF THE LARYNX • Larynx is our VOICE BOX. • The Larynx extends from Laryngeal inlet above to the lower border of Cricoid cartilage below. • Functions of Larynx : 1. Protective function 2. Voice production
    2. 2. INFANTILE LARYNX  Lumen narrower  More funnel-shaped  Narrowest part is the junction of the sub- glottic larynx with the trachea  Cartilages are much softer and hence collapses more easily on forced inspiration.  Placed more high up.
    3. 3. EMBRYOLOGY  Primitive larynx: cranial end of laryngo- tracheal groove  Laryngeal mucosa: endoderm  Laryngeal cartilages & muscles: mesenchyme
    4. 4. EMBRYOLOGY  Epiglottis- hypobranchial eminence  Upper part of thyroid cartilage-4th arch  Lower part of thyroid cartilage, cricoid, corniculate, cuneiform, intrinsic muscles-6th arch  Upper part of body& lesser cornu of hyoid-2nd arch  Lower part of body & greater cornu of hyoid-3rd arch
    5. 5. STRUCTURE OF LARYNX  Laryngeal framework is formed by – 1. Cartilages 2. Membranes & ligaments 3. Muscles of larynx
    6. 6. LARYNGEAL CARTILAGES  Paired  Arytenoid cartilage  Corniculate cartilage  Cuneiform cartilage  Unpaired:  Thyroid cartilage  Cricoid cartilage  Epiglottis
    7. 7. THYROID CARTILAGE  Hyaline cartilage  Largest.  Encloses the larynx anteriorly and laterally  Two alae  Ossification.
    8. 8. THYROID CARTILAGE Internal surface gives attachments to –Thyro-epiglottic ligament, paired vocal and vestibular ligaments and Vocalis,Thyro- arytenoid and Thyro-epiglotticus muscles.
    9. 9. CRICOID CARTILAGE Hyaline cartilage Strongest Shape: Signet ring Lamina – flat portion Only complete annular support of the larynx Articulates with Inferior cornu of the thyroid cartilage
    10. 10. EPIGLOTTIS  Fibro elastic cartilage  Leaf-shaped structure  Petiole – small narrow stalk like portion of the epiglottis attached to the thyroid cartilage.  Contains a tubercle on its posterior surface.
    11. 11. EPIGLOTTIS (contd.)
    12. 12. ARYTENOID CARTILAGES  Mostly hyaline cartilage  Smaller in size  Responsible for opening and closing of the larynx  Shape: pyramidal
    13. 13. ARYTENOID CARTILAGES  Anterior  Vocal process - receives the attachment of the mobile end of eachVC  Lateral  Muscular process  Articulation  Cricoarytenoid joint
    14. 14. CORNICULATE CARTILAGES Fibro elastic  Cartilages of Santorini  Small cartilages above the arytenoid and in the aryepiglottic folds
    15. 15. CUNEIFORM CARTILAGES  Fibro elastic cartilages  Cartilages of Wrisberg  Elongated pieces of small yellow elastic cartilage in the aryepiglottic folds
    16. 16. TRITICEOUS CARTILAGES  Cartilago triticea  Small elastic cartilage in the lateral thyrohyoid ligament
    17. 17. LARYNGEAL LIGAMENTS  Extrinsic  Thyrohyoid membrane and ligaments  Cricothyroid membrane and ligaments  Cricotracheal ligament  Hyo-epiglottic ligament
    18. 18. LARYNGEAL LIGAMENTS  Intrinsic  Quadrangular membrane  Conus elasticus (cricovocal membrane)  Median cricothyroid ligament  Vocal Ligament  Thyroepiglottic ligament
    19. 19. EXTRINSIC LIGAMENTS Thyrohyoid membrane MedianThyrohyoid ligament – thickened median portion Lateral thyrohyoid ligament – thickened posterior border - where cartilago triticea is often found
    20. 20. EXTRINSIC LIGAMENTS Thyrohyoid membrane pierced on each side by: 1. Superior laryngeal vessels 2. Internal branch of superior laryngeal nerve
    21. 21. EXTRINSIC LIGAMENTS  Cricothyroid membrane and ligaments  May be pierced for emergency tracheotomy (cricothyrotomy)
    22. 22. EXTRINSIC LIGAMENTS  Crico tracheal Ligament  Attaches the cricoid cartilage to the first attached ring  Hyo-epiglottic Ligament  Connects the anterior surface of epiglottis with Hyoid bone.
    24. 24. INTRINSIC LIGAMENTS  Elastic membrane  Divided into upper and lower parts by the ventricle of the larynx  Forms the fibrous framework of larynx.
    25. 25. INTRINSIC LIGAMENTS  Quadrangular membrane  Upper part of the elastic membrane  Boundaries  Epiglottis , arytenoid, corniculate cartilage, false cord  Forms part of wall between upper pyriform sinus and laryngeal vestibule
    26. 26. INTRINSIC LIGAMENTS  Conus elasticus (cricovocal membrane)  Lower part of elastic membrane  Composed mainly of yellow elastic tissue  Median cricothyroid ligament – thickened anteior part  Vocal Ligament – free upper edge
    27. 27. INTRINSIC LIGAMENTS  Boundaries Inferior: superior border of cricoid cartilage Superoanterior: deep surface of angle thyroid cartilage Superoposterior: vocal process of arytenoid cartilage  Thyro-epiglottic ligament
    29. 29. CAVITY OF THE LARYNX  Divided into 3 parts:  Vestibule  Ventricle  Sub glottic space
    30. 30. CAVITY OF THE LARYNX  Vestibule – boundaries:  Anterior: posterior surface of epiglottis  Posterior: interval between arytenoid cartilages  Lateral: inner surface of ary-epiglottic folds and upper surfaces of the false cord
    31. 31. CAVITY OF THE LARYNX • Ventricle • Saccule – conical pouch at anterior part of the ventricle. Lies between Inner surface of thyroid cartilage and false cord. It has numerous mucous glands opening into the surface of its lining mucosa for lubricating the vocal cords. • SUBGLOTTIC SPACE
    32. 32. RIMA GLOTTIDIS  Space between free margin of true cords  Two portions – Anterior or Inter- membranous (3/5 th) Posterior or Inter- cartilagenous (2/5 th)
    33. 33. RIMA GLOTTIDIS
    34. 34. CAVITY OF THE LARYNX False Cords (ventricular bands) Anteriorly: angle of the thyroid cartilage Posteriorly: bodies of the arytenoid cartilage
    35. 35. CAVITY OF THE LARYNX True cords Voice production Protection of lower respiratory tract Anteriorly,: angle of thyroid cartilage Posteriorly : vocal processes of the arytenoid cartilages Enclose vocal ligament and a major part of the vocalis muscle
    36. 36. VOCAL CORDSVOCAL CORDS  The lamina propria consists of three layers. The most superficial consists of fibrous substance similar to gelatin, and is loosely attached to the underlying vocal ligament  The intermediate layer consists of elastic fibres, and the deep layer is formed of collagen fibres; these two layers collectively form the vocal ligament  Fibres of the vocalis muscle form the fifth layer of the vocal folds
    37. 37. POTENTIAL TISSUE SPACES  REINKE`S SPACE:- Between superficial layer of lamina propria and mucosa of vocal cords.  PARAGLOTTIC SPACE:- between the membranes of the larynx and the thyroid cartilage
    38. 38. PRE-EPIGLOTTIC SPACE  Pre-epiglottic space of boyer:- • Between hyoid & thyrohyoid membrane anteriorly and infrahyoid epiglottis Posteriorly. • Fat filled • Sparse blood supply, so relatively radio- resistant • Invasion of this space- Stage T3 in TNM classification.
    39. 39. JOINTS OF LARYNX  Cricothyroid joint 1. Synovial joint 2. Formation -inferior horn of thyroid cartilage and a facet in the cricoid Two types movements: Rotation Gliding
    40. 40. JOINTS OF LARYNX  Crico-arytenoid jt.- 1. Synovial joint 2. Formation-base of arytenoid and facet on the upper border of cricoid lamina 3. Types of movement- A) Rotatory along vertical axis, causing abduction & adduction of vc b) gliding
    41. 41. MUSCLES OF LARYNX  Extrinsic  Intrinsic
    42. 42. EXTRINSIC MUSCLES OF LARYNX Attach larynx to surrounding structures.  DIRECT ELEVATORS: Stylopharyngeus, Palatopharyngeus, Salpingopharyngeus, Thyrohyoid  INDIRECT ELEVATORS : Mylohyoid, Geniohyoid , Stylohyoid & Digastric  DEPRESSORS: Sternothyroid, Sternohyoid,Omohyoid
    43. 43. DepressorDepressor musclesmuscles OriginOrigin InsertionInsertion ActionAction SternohyoidSternohyoid manubrium ofmanubrium of sternum andsternum and medial end ofmedial end of clavicleclavicle oblique line of theoblique line of the thyroid cartilagethyroid cartilage depresses/stabilizesdepresses/stabilizes the hyoid bonethe hyoid bone OmohyoidOmohyoid superior bordersuperior border of scapula nearof scapula near thethe suprascapularsuprascapular notchnotch inferior border ofinferior border of hyoid bonehyoid bone depresses, retractsdepresses, retracts and steadies theand steadies the hyoid duringhyoid during swallowing andswallowing and speakingspeaking SternothyroidSternothyroid MuscleMuscle SuperiorSuperior attachment:attachment: oblique line ofoblique line of thyroidthyroid cartilage.cartilage. InferiorInferior attachment:attachment: posterior surfaceposterior surface of manubrium ofof manubrium of sternum.sternum. It depresses theIt depresses the hyoid bone andhyoid bone and larynxlarynx
    44. 44. PrimaryPrimary ElevatorElevator musclesmuscles OriginOrigin InsertionInsertion ActionAction StylopharyngeusStylopharyngeus styloidstyloid process ofprocess of temporaltemporal bonebone posterior andposterior and superior borders ofsuperior borders of thyroid cartilagethyroid cartilage withwith palatopharyngeuspalatopharyngeus musclemuscle elevates the pharynxelevates the pharynx and larynx and expandsand larynx and expands the sides of the pharynxthe sides of the pharynx SalpingopharyngeuSalpingopharyngeu ss cartilaginouscartilaginous part of thepart of the auditoryauditory tubetube blends withblends with palatopharyngeuspalatopharyngeus musclemuscle elevates the pharynxelevates the pharynx and larynx and opensand larynx and opens the orifice of thethe orifice of the auditory tube duringauditory tube during swallowingswallowing PalatopharyngeusPalatopharyngeus hard palatehard palate and palatineand palatine aponeurosisaponeurosis lateral wall oflateral wall of pharynxpharynx tenses the soft palatetenses the soft palate and pulls the walls ofand pulls the walls of the pharynx superiorly,the pharynx superiorly, anteriorly and mediallyanteriorly and medially during swallowingduring swallowing
    45. 45. SecondarySecondary ElevatorElevator musclesmuscles OriginOrigin InsertionInsertion ActionAction GeniohyoidGeniohyoid inferior mentalinferior mental spine of mandiblespine of mandible body of hyoidbody of hyoid bonebone pulls the hyoid bonepulls the hyoid bone anterosuperiorly, and shortensanterosuperiorly, and shortens the floor of the mouth andthe floor of the mouth and widens the pharynxwidens the pharynx DigastricsDigastrics anterior belly-anterior belly- digastric fossa ofdigastric fossa of mandible,mandible, posterior belly-posterior belly- mastoid notch ofmastoid notch of temporal bonetemporal bone intermediateintermediate tendon to bodytendon to body and greater hornand greater horn of hyoid boneof hyoid bone depresses the mandible anddepresses the mandible and raises the hyoid bone. Also, itraises the hyoid bone. Also, it steadies the hyoid bone duringsteadies the hyoid bone during swallowing and speakingswallowing and speaking MylohyoidMylohyoid mylohyoid line ofmylohyoid line of mandiblemandible raphe and body ofraphe and body of hyoid bonehyoid bone elevates the hyoid bone, floorelevates the hyoid bone, floor of the mouth and the tongueof the mouth and the tongue during swallowing and speakingduring swallowing and speaking StylohyoidStylohyoid styloid process ofstyloid process of the temporalthe temporal body of hyoidbody of hyoid bonebone elevates and retracts the hyoidelevates and retracts the hyoid bone, thereby elongating thebone, thereby elongating the
    47. 47. EXTRINSIC MUSCLES OF LARYNX (contd.)
    48. 48. INTRINSIC MUSCLES OF LARYNX Interarytenoid muscle  Transverse  Oblique  Post. Cricoarytenoid m.  Lateral cricoarytenoid m.  Thyroarytenoid m.  Cricothyroid m.
    49. 49. Muscles Controlling Movements of the Vocal Cords IntrinsicIntrinsic MusclesMuscles OriginOrigin InsertionInsertion ActionAction Posterior cricoarytenoid posteriorposterior surface of thesurface of the lamina of thelamina of the cricoid cartilagecricoid cartilage muscular processmuscular process of the arytenoidof the arytenoid cartilagecartilage Abduct vocal cordAbduct vocal cord Interarytenoid m., transverse posteriorposterior surface of thesurface of the arytenoidarytenoid cartilagecartilage posterior surfaceposterior surface of theof the contralateralcontralateral arytenoidarytenoid cartilagecartilage Closes posteriorCloses posterior part of rimapart of rima glottidis byglottidis by approximatingapproximating arytenoidarytenoid cartilagescartilages
    50. 50. Muscles Controlling Movements Of The Vocal Cords Intrinsic Muscles Origin Insertion Action Lateral Crico- arytenoid Lateral part of upper border of arch of Cricoid Muscular process of Arytenoid Adductor of the vocal cord. Crico-thyroid Lower border and lateral surface of Cricoid Inferior cornu and lower border of Thyroid cartilage. Tensor of Vocal cords
    51. 51. MUSCLES CONTROLLING THE LARYNGEAL INLET Intrinsic MusclesIntrinsic Muscles OriginOrigin InsertionInsertion ActionAction Interarytenoid m., oblique muscular processmuscular process of the arytenoidof the arytenoid cartilagecartilage posterior surface ofposterior surface of the contralateralthe contralateral arytenoid cartilage,arytenoid cartilage, near its apexnear its apex draws arytenoiddraws arytenoid cartilages together,cartilages together, adducting the vocaladducting the vocal folds (closure offolds (closure of glottis)glottis) Thyroepiglottic inner surface ofinner surface of the thyroidthe thyroid cartilage near thecartilage near the laryngeallaryngeal prominenceprominence lateral surface oflateral surface of the epiglotticthe epiglottic cartilagecartilage draws the epiglotticdraws the epiglottic cartilage downwardcartilage downward
    52. 52. MUCOUS MEMBRANE  Stratified squamous epith.: over vocal cords and upper part of vestibule of larynx  Ciliated columnar epith.: remainder of the cavity  Mucous glands:  Ventricles and sacculi  Posterior surface of epiglottis  Margins of aryepiglottic folds  Reinke’s layer of connective tissue: No glands and no lymph vessels
    53. 53. NERVE SUPPLY  Inferior (recurrent) laryngeal n. Motor – all intrinsic laryngeal muscles of SAME side (except cricothyroid) and interarytenoid muscle of BOTH sides Sensory – areas below the glottis
    54. 54. NERVE SUPPLY  Supplied by Vagus nerve:  Superior laryngeal n. Internal branch (sensory) – areas above the glottis External branch (motor and sensory) Motor – Cricothyroid muscle Sensory – Anterior infraglottic larynx at level of cricothyroid membrane
    55. 55. ARTERIAL SUPPLY  Area above vocal cords  Superior laryngeal artery  Area below vocal cords  Inferior laryngeal artery
    56. 56. VENOUS DRAINAGE  Upper Larynx  Superior laryngeal vein  Lower Larynx  Inferior laryngeal vein
    57. 57. LYMPHATIC DRAINAGE  Supraglottis:- upper deep cervical nodes  Glottis:- sparse, except for a small lymph node in the cricothyroid membrane delphian node  Subglottis:- lower deep cervical and mediastinal lymph nodes via prelaryngeal and paratracheal nodes