Larynx Flashcards
Larynx Overall Functions
-Protection of airways
-enable one to hold breath /. breathe
-produces phonation
Larynx Structural components
-Hyoid Bone
-Thyroid Cartilage
-Cricoid Cartilage
-Epiglottis
-Corniculate Cartilages
-Arytenoid Cartilages
Larynx Positioning
-Suspended from Hyoid Bone
-Superior to trachea
-anterior to oesophagus
Ventricular folds (false vocal folds)
-superior to true vocal folds
-function for protection of airways
-prevent food entering trachea when swallowing
-draped in mucosa
Supraglottal region / Vestibule
-false vocal cords (walls)
-laryngeal ventricle (space)
Rima Glottis
-between true vocal folds
Subglottal Antium
-below true vocal folds
-conus elasticus (walls)
Pyriform Sulcus
-lateral to aditus laryngis
-allows for fluid to bypass teh larynx between swallows
-transit for food and liquid during swallowing
True Vocal Folds
-vocal ligament
-formed by superficial border of conus elasticus
True Vocal Cords structure: superficial –> deep
Cover:
-epithelium
-superficial layer of lamina propria
-intermediate layer of lamina propria
Body:
-deep layer of lamina propria
-vocalis muscle
True Vocal Cords: Superior View
Membranous part is anterior (front) and lies between thyroid cartilage and tips of vocal processes of arytenoid cartilages
-60% of length
Cartilaginous part is posterior (back) lies between the vocal processes and most rear point on medial surface of arytenoid cartilages
-40% of length
Vocal Fold Movements
-abduction (open/away from midline)
-adduction/medial compression (closed / toward midline)
Laryngeal Joints: Cricoarytenoid Joints
-between arytenoid and cricoid cartilages
-allows for vocal cords to open and close to varying degrees (adduct/abduct/medial compression)
-due to rocking / twisting/ sliding motion
Laryngeal Joints: Cricothyroid Joint
-between thyroid and cricoid cartilages
-rotating and gliding allows thyroid cartilage to move forward and back –> tension change of vocal cords
-pitch changes
Glottis
combination of the space between the vocal cords (rima glottis) and the vocal cords
Glottis Shapes: normal respiration
abducted
Glottis Shapes: forced respiration
wider abduction
Glottis Shapes: Phonation
adduction/medial compression
Larynx Musculature: Intrinsic vs Extrinsic
Intrinsic- fine adjustments associated with control of phonation
Extrinsic - Laryngeal musculature system works as a unit
-laryngeal elevation
-laryngeal depression
Laryngeal Musculature: Intrinsic
-origin and insertion on laryngeal cartilages
-innervation by vagus (X) nerve
-open and close vocal cords
-tense and relax vocal cords
-types=
adductors/abductors,
tensors/ relaxers
auxillary musculature
Laryngeal Musculature: Extrinsic
-have one attchment to non laryngeal structure
-elevate or depress the larynx
major types=
hyoid and laryngeal elevators
hyoid and laryngeal depressors
e.g Sternohyoid and mylohyoid
Vocal fold adjustments: Voiced vs Voiceless Sounds
-voiced= adduction
-voiceless= abduction
Vocal Fold Adduction : Muscles involved
-movemnet towards teh midline
-Lateral Cricoarytenoid Muscles - adduct the anterior 2/3s of vocal cords
-arytenoid Muscles adduct the posterior 1/3 of vocal cords
Lateral Cricoarytenoid Muscle
-closes glottis anteriorly (2/3)
- attaches at lateral margins of the cricoid cartilage and muscular process of teh arytenoid cartiladges
-swings arytenoids forward and down in adduction
Arytenoid Muscles: obliques and transverse
action: close glottis by drawing arytenoids together posteriorly (1/3)
-attachments at left and right arytenoid cartilages
-transverse runs horrizontally between arytenoids
-obliques join in an x shape
Vocal Fold Abduction : muscles involved
-movement of folds away from the midline
-posterior cricoarytenoid muscles= primary abductors
-conuc elasticus = weaker abductor with downward pull
Posterior Cricoarytenoid
action= open glottis
-attaches at cricoid cartilage and arytenoid cartilages (muscular processes)
-rotates arytenoids and separates vocal folds
Vocal fold Length Change
-lengthen with contraction of cricothyroid muscles
-shorten with contraction of thyroarytenoid muscles
Tensor Muscle: Cricothyroid
action= stretch and thin the vocal folds
attches at anterior cricoid cartilage and thyroid cartilage
-contracts and tilts the the thyroid cartilage forward, tensing vocal folds
Tensor Muscle: Thyroarytenoid Muscles
- attach at internal thyroid cartilage near notch and arytenoid cartilages
-inner parts = Thyrovocalis –> chnage tension and modify sound produced
-outer parts= Thyromuscularis –> pull arytenoids closer to thyroid cartilage and thus shorten/ bulk up vocal cords
Vebbtricular fold (false vocal cords) adjustments
- configuration and position changes with contributions of upward extending fibres of aryepiglottic and thyroepiglottic muscles
Epiglottic adjustments
configuration and position chnages with contributions of aryepiglottic muscles
Hyoid and Laryngeal Elevators
-suprahyoid muscles
- stylohyoid / mylohyoid / hyoglossus / digastric
-superior to hyoid bone to constrict to raise the larynx
-elevate laryngeaus aditus (laryngeal opening) so epiglottis covers it in our swallow
-elevation can cause tension in conus elasticus and increase pitch
Hyoid and Laryngeal Depressors
Infrahyoid Muscles:
- thyrohyoid / omohyoid / sternohyoid / sternothyroid
-contract and depress the hyoid bone and larynx
- may reduce tension in conus elasticus and decrease pitch
Innervation of Laryngeal Muscles
-branches of Vagus Nerve (CN X)
-superior laryngeal nerve and recurrent laryngeal nerve
