Module 3.1: Phonatory Anatomy Flashcards
Larynx Functions
-Biological roles
-Respiratory Roles
-Flow air into and out of lower respiratory tract
-Protection
-Prevents air from escaping from lungs when valving is needed
-Prevents foreign substances from entering the lungs
-Expels foreign substances threatening the trachea
-Swallowing
-Protective mechanisms, preventing food/liquid from entering the lungs
-Non-biological role
-Sound generator
Larynx: Structural Components
-Bone
-Cartialges
Larynx: Links & Spaces
-Joints
-Membranes & Ligaments
-Laryngeal Cavity
Larynx: Muscles
-Extrinsic laryngeal muscles
-Intrinsic laryngeal muscles
Hyoid Bone
-U-shape bone
-2 greater cornua
-2 lesser cornua
-Body
-Suspends larynx with muscles and ligaments
-Serve as attachment for tongue muscles and extrinsic laryngeal muscles
Thyroid Cartilage
-Largest laryngeal cartilage
-Unpaired, shield-like
-2 laminae
-2 superior cornua
-2 inferior cornua
-Thyroid Notch
-Angle of Thyroid
-Laryngeal prominence
-Hyaline cartilage
Cricoid Cartilage
-Inferior aspect of larynx
-Unpaired, signet ring-shape
-Cricoid arch
-Lamina
-Articular facets
-Hyaline cartilage
Arytenoid Cartliages
-Paired, pyramidal shape
-Muscular process (towards back)
-Vocal process (towards front)
-Apex
-Located on superior margin of cricoid lamina
-Movements: Rocking & Gliding
Epiglottis Cartilage
-Unpaired, leaf shape
-Posterior to hyoid bone and root of tongue
-attached inferiorly to thyroid angle
-Attached superiorly to hyoid bone
-Elastic cartilage
-Function: airway protection during swallowing
-Inversion movement to close laryngeal additus
Corniculate Cartilages
-Paired, elastic cartilage
-On top of arytenoids (apex)
-No functional role in voice production
Cuneiform Cartilages
-Paired elastic cartilage
-Embedded in aryepiglottic folds
-Stiffen and support aryepiglottic folds
-No functional role in voice production
Cricothyroid Joint
-Cricoid articular facet and thyroid inferior horns
-Rocking movement
-Thyroid rocks forward and downward
-Cricoid rocks backward and upwards
-Elongates VF and increases tension
Cricoarytenoid Joint
-Cricoid articular facet and arytenoid articular facet
-Rocking and some gliding movement
-Downward and inward
-VF adduction
-Upward and outward
-VF abduction
Role of Extrinsic Membrane and ligaments
-Connect laryngeal cartilages to other structures
-Provide anatomic support to larynx
-Membranes
-Flat sheet of connective tissue
-Connect cartilages
-Lines cavities
-Ligaments
-Connect bones and cartilages
-Thicker than membranes
Thyrohyoid Membrane
-Connects thyroid laminae and hyoid bone
-Suspends larynx from above
Thyrohyoid ligaments
-Lateral (posterior) thyrohyoid ligaments
-Connects thyroid superior horns to hyoid greater horns
-Median (anterior) thyrohyoid ligament
-Connects thyroid laminae to hyoid body
Hyoepiglottic Ligament
-Connects hyoid bone to epiglottis
Cricotracheal Ligament (membrane)
-Connects inferior border of cricoid to first tracheal ring
-Allows translation of movement between cricoid and trachea
Conus Elasticus
-Lateral cricothyroid ligament (membrane)
-Lateral portion of conus elasticus
-Connects superior border of cricoid to vocal process of arytenoid and to thyroid angle
-Vocal ligament
-Medial portion of true VFs
- Median cricothyroid ligament
-Connects cricoid to inferior border of thyroid
Quadrangular Membrane
-Connects lateral margins of epiglottis to thyroid angle and to arytenoid (corniculate) cartilages
-Vestibular ligament
-Vestibular (ventricular) folds (false VFs)
-Terminate superiorly as aryepiglottic folds
Supraglottic Space
Above VF
Supraglottic Space Components
-Laryngeal Aditus
-Laryngeal Vestibule
-Pyriform Sinuses
-Ventricle
Laryngeal Aditus
Entrance of Larynx
Laryngeal Vestibule
Below laryngeal aditus
Pyriform Sinuses
Depressions on side of larynx
Ventricle
Space between false and true VFs
Glottis
Between true VFs
Subglottic space
Below true VFs
Vocal Folds
Membranous and Cartilaginous portions
Anterior Commissure
VFs origination
Posterior Commissure
Where VFs attach to vocal process
Extrinsic Laryngeal Muscles
-One attachment to structures outside larynx
-Includes supplementary muscles
-Support and fixation of larynx in neck
-2 groups: Suprahyoid and Infrahyoid
Suprahyoid
Elevates Larynx
Infrahyoid
Depresses Larynx
Mylohyoid
Forms bulk of floor of mouth (FOM)
Mylohyoid Innervation
CNV
Mylohyoid Action
Hyoid Fixed: Depresses Mandible
Mandible Fixed: Elevates and protrudes hyoid, elevates FOM and tongue
Digastric: Anterior Belly
Part of FOM
Digastric: Anterior Belly Action
Hyoid Fixed: Depresses mandible
Mandible Fixed: Elevates and Protrudes hyoid bone
Digastric: Anterior Belly Innervation
CN V
Digastric: Posterior Belly Action
Elevates and retracts hyoid bone
Digastric: Posterior Belly Innervation
CN VII
Stylohyoid
Superficial to posterior belly of digastric
Stylohyoid Action
Elevates and retracts hyoid bone
Stylohyoid Innervation
CN VII
Geniohyoid
-Superior to mylohyoid
-Runs parallel to anterior belly of digastric
-FOM muscle
Geniohyoid Action
-Hyoid Fixed: depresses mandible
-Mandible Fixed: elevates and protrudes hyoid
Geniohyoid Innervation
C1 via CN XII
Omohyoid
-Anterior-lateral surface of neck
-2 bellies: inferior and superior
Omohyoid Action
Depresses hyoid bone
Omohyoid Innervation
C1-C3 (ansa cervicalis) via CN XII
Sternohyoid
Anterior-lateral surface of the neck
Sternohyoid Action
Depresses hyoid bone
Sternohyoid Innervation
C1-C3 (ansa cervicalis) via CN XII
Thyrohyoid
-Anterior surface of the neck
-Deep to and mostly covered by sternohyoid and omohyoid
Thyrohyoid action
Decreases distance between hyoid bone and thyroid cartilage
Thyrohyoid Innervation
C1 via CN XII
Sternothyroid
-Anterior surface of neck
-Deep to and mostly covered by sternohyoid and omohyoid
Sternothyroid Action
Depresses thyroid cartilage
Sternothyroid Innervation
C1-C3 (ansa cervicalis) via CN XII
Intrinsic Laryngeal Muscles
-Control of Sound Production
-Always act in pairs
Effects on shape of Glottis
-Adductors (close VFs)
-Abductors (open VFs)
Effects on Vibratory Behavior of VFs
-Tensors (elongate VFs)
-Relaxers (shorten VFs)
Adjustment of larynx in 2 ways
- Medial Compression
- Longitudinal tension
Medial Compression
Force with which VFs brought together
Longitudinal tension
Stretching Forces
Thyroarytenoid
-Bulk of VFs (main vibrating mass of VFs)
2 Muscle Masses of Thyroarytenoid
-Thyrovocalis
-Thyromuscularis
Thyroarytenoid Innervation
CN X, RLN Branch
Thyroarytenoid Action
- Primary regulator of longitudinal tension
a.When unopposed:
Relaxes (shortens) VFs
-May assis in adducting glottis by drawing muscular process forward
b. When opposed by other muscles:
Tenses (elongates VFs)
Cricothyroid Muscle
-Fan shaped muscle with two parts:
1. Pars recta (straight part)
2. Pars oblique (oblique part)
Cricothyroid Innervation
CN X, SLN branch (external)
Cricothyroid Action
- Increases VF tension
- Reduces distance between cricoid arch and thyroid lamina
a. Primary Action: tilts thyroid downward (if cricoid fixed)
b. Tilts cricoid upwards (if thyroid fixed)
c. Can minimally slide thyroid forward (pars oblique)
Posterior Cricoaytenoid
Only abductor muscle of larynx
Posterior Cricoarytenoid Innervation
CN X, RLN Branch
Posterior Cricoarytenoid Action
- Rotates arytenoid (vertical fibers)
a. Abducts and elevates vocal process - Help stabilize arytenoid (fanning fibers)
Lateral Cricoarytenoid
- Deep to thyroid, on sloping lateral border of cricoid
- Adductor muscle of larynx
Lateral Cricoarytenoid Innervation
CN X, RLN branch
Lateral Criocarytenoid Action
Rotates vocal processes toward midline
-Adduction of VFs
Interarytenoids
- 2-part muscle on posterior surface of arytenoids
a. Oblique (superficial)
b. Transverse (deep) - Adductor muscle
Interarytenoids Innervation
CN X, RLN branch
Interarytenoids Action
Approximate arytenoids
a. Adducts VFs
b. Close the posterior glottis
VF Histology layers
- Epithelium
- Lamina Propria
a. Superficial layer (most pliable)
b. Intermediate layer (somewhat pliable)
c. Deep layer (Stiff) - Vocalis Muscle (main body of VFs)
Lamina Propria
- Superficial layer=Reinke’s Space
a. Loose fibrous components - Intermediate layer
a. Elastic Fibers - Deep Layer
a. Collagenous fibers
Epithelium
- Stratified squamous epithelium
- Maintains VF shape
Basement Membrane Zone
- Transitional area between epithelium and superficial layer LP
a. secures epithelium to superficial layer - VF nodules
a. Primary damage site
b. Disorganization and increased thickness in BMZ (these changes not found in polyp)
3-Layer VF Scheme
- Mucosa (Epithelium & Superficial Layer LP)
- Ligament (Intermediate and Deep Layer LP)
- Muscle
2-Layer scheme
- Cover (Epithelium, Superficial & Intermediate layer LP)
- Body (Deep Layer LP & Muscle)
VF Development
- Infants: VF is uniform structure
- Toddlers (1-4 yo): immature ligament
- Adolescents (15yo): three layers of LP
VF in Geriatrics
- Lamina Propria
a. Tissue stiffer
b. More viscosity
c. Change greater in males - Degeneration of Mucous glands
- Decrease in Vascular supply
