anatomy 5 phonation anatomy b

Speech mechanism = mechanical system : 

Speech mechanism = mechanical system -power supply – pressure - respiration -vibrating elements - phonation -valves and filters - articulation -vibrating element Larynx - vocal folds vibrate rapidly, allowing air stream to pass and generate a tone as air molecules from below strike air molecules above

Larynx : 

Larynx musculocartilaginous structure that sits superior to trachea at midline in anterior neck Inferior to hyoid bone At level of C3-6 Keep in mind great variability will be seen among individuals in structures of laryngeal mechanism

Laryngeal Functions: : 

Laryngeal Functions: 1-biological function in respiration - sphincter closes to protect airway below from foreign debris; coughing: forceably expels foreign debris by opening laryngeal valve once subglottal pressure is increased prevents air from escaping from lungs during thoracic fixation swallowing 2-nonbiological function sound production for speech – i.e. phonation -depends on vocal folds - muscle tissue within larynx which acts as vibratory source; can be modified in length, tension, and medial displacement (abduction/adduction) also creates specific speech sounds – e.g. /h/

Slide 5: 

Laryngeal Framework

Supportive framework: bone and cartilages : 

Supportive framework: bone and cartilages Hyoid bone -point of attachment for some extrinsic laryngeal muscles -22-23 muscles attach to this bone! -not directly attached to any other bone -held in position by hyoid sling muscles and ligaments from tongue, chin, temporal bone, and extrinsic laryngeal muscles -is very mobile U-shaped At level of C3 Body/corpus Posteriorly - greater horns/cornu Lesser horn/cornu -

Cartilages of larynx : 

Cartilages of larynx 3 unpaired: thyroid - hyaline cricoid - hyaline epiglottis - elastic cartilage 3 paired: arytenoid - hyaline corniculate - elastic cuneiform - elastic -some cartilages ossify with age, but flexible during youth

Slide 9: 

Epiglottis Thyroid Thyroid: largest of cartilages thyroid laminae - boney plates that form a wedge shape angle of thyroid - point where the two plates fuse thyroid notch - point where not fused posteriorly - open wedge superior cornu - articulates with greater horn of hyoid inferior cornu - articulate with the cricoid below

Slide 10: 

Epiglottis Cricoid cartilage lowermost border of larynx located immediately superior to 1st tracheal ring anterior arch - anterior portion posterior quadrate lamina - hexagon or like a signet ring laterally - see facets where thyroid and arytenoids cartilages articulate Cricoid Arytenoids

Slide 11: 

Arytenoid cartilages pair sit atop cricoid posterior lamina roughly pyramidal shape with three points apex - uppermost point of cartilage muscular process - more posterior/lateral; point of attachment for some important laryngeal muscles vocal process - lies more anterior/medial; point of attachment for the vocal ligament See prior slide

Other less critical cartilages : 

Other less critical cartilages Corniculate cartilages vestigial structures two tiny elastic cartilages that sit atop the apex of arytenoid embedded within aryepiglottic membrane Cuneiform cartilages embedded within aryepiglottic folds lateral to corniculates - membrane enclosing ligament and muscle fibers extending from the epiglottis back to apex of arytenoid cartilages function: Possibly stiffen folds to help keep larynx open

Slide 14: 

Epiglottis Epiglottis Unpaired flexible elastic cartilage lies posterior to hyoid bone held in place by ligaments attaching to thyroid, epiglottis, tongue epiglottis can be visible in child’s larynx Function: -prevents food from entering larynx during swallowing like a trapdoor movement as larynx lifts up and anterior, epiglottis gets bent, allowing bolus of food to go to esophagus little role in speech function - but would affect resonance possibly a vestigial structure

Slide 17: 

1-Cricoarytenoid joint muscular process of arytenoid cartilage sits atop posterior cricoid a diarthrodial joint that allows a rocking and gliding motion which affects movement of vocal process of arytenoid for ab-or ad-duction Laryngeal Joints

Slide 18: 

2-Cricothyroid joint Inferior horn of thyroid sits atop lateral cricoid diarthrodial joint that permits a rotational movement around the joint critical for placing tension on vocal folds within and raising pitch of the voice Laryngeal Joints

External Laryngeal membranes : 

External Laryngeal membranes 1-Hyothyroid membrane and ligaments space between hyoid and thyroid occupied by this membrane with thickening at midline and lateral because of ligaments embedded within 2-Cricotracheal membrane connects lower border of cricoid cartilage to upper tracheal ring See previous slide

Intrinsic laryngeal membranes : 

Intrinsic laryngeal membranes 3- Conus elasticus - or cricovocal membrane sheet of tissue that lines and connects the thyroid, cricoid and arytenoid cartilages from the superior border of the cricoid extending upward to true vocal folds Vocal ligament - Extends from the vocal process of the arytenoid to the thyroid arch this is medial portion of each vocal fold 4- Quadrangular membrane from lateral edges of epiglottis and thyroid cartilage -fibers course downward and posteriorly to attach at corniculate cartilages and medial arytenoid end within larynx as a free, thickened border called the ventricular ligaments and often called the false vocal folds or ventricular folds

Slide 22: 

Aryepiglottic folds superior margin of quadrangular membrane lined with aryepiglottic muscles embedded within folds near arytenoid are cuneiform and corniculate cartilages Valleculae two depressions spaces between epiglottis and root of tongue on either side of medial ligament/fold important space during swallowing evaluations - can see pooling of material in valleculae Mucous membrane Lines the whole laryngeal tract - continuous with mouth above and trachea below

Slide 23: 

Tongue Valleculae Pyriform Sinus Glottis Aryepiglottic fold Epiglottis

Interior larynx : 

Interior larynx Aditus laryngis -“entrance” i.e. epiglottis to aryepiglottic folds to apex of arytenoids Pyriform sinus -depression between thyrohyoid membrane laterally and aryepiglottic folds medially -important in swallowing as fluid can pool here and later enter larynx Glottis - space between vocal folds – present when VFs abducted

Intrinsic Larynx : 

Intrinsic Larynx Ventricular folds - false vocal folds -Cannot become tense, soft and flaccid -Move somewhat when the arytenoid moves, but do not vibrate -False glottis - space between these folds - Clinically: on occasion you may see people use these folds for phonation i.e. ventricular dysphonia; vocal quality will be very rough and strident Vestibule - region between aditus and ventricular folds Ventricle (Ventricle of Morgagni) - region between ventricular folds and vocal folds

Slide 26: 

Aryepiglottic fold Aditus laryngus

Vocal folds : 

Vocal folds Anteriorly start at angle of thyroid (below the notch) Course posteriorly to attach on anterolateral surface of arytenoid cartilages Medial border are free margins look glossy white when viewed from above Consists of 5 tissue layers: 1-epithelial 2-4 lamina propria 2 layers elastin (very stretchy) 1 layer collagen (not stretchy) layers 3-4 vocal ligament 5- muscle layer – thyrovocalis

Glottis : 

Glottis Variable sized opening between vocal folds Membranous glottis - anterior 3/5 portion bounded by vocal ligament; most active portion when viewed under photography Cartilagenous glottis - posterior 2/5 of glottis; bounded by vocal process and medial surface of arytenoid cartilages Size -Posteriorly in males at rest: 8 mm -At inhalation: can double in size

Slide 30: 

Tongue Valleculae Pyriform Sinus Glottis Aryepiglottic fold Epiglottis

Muscles of the larynx : 

Muscles of the larynx supplied by cranial nerves V, VII, XII & ***X Extrinsic laryngeal muscles - at least one attachment outside the larynx -Function to support and fixate the larynx -elevate larynx during swallowing -elevate larynx during pitch change Intrinsic muscles - both attachments within the larynx - Function in the control of sound production - Close airway during swallowing

Extrinsic laryngeal muscles : 

1. Sternothyroid Located in anterior neck Origin - manubrium (of the sternum) and first costal cartilage Course - upward Insert - lateral thyroid lamina Function - pulls thyroid cartilage down - depressor Extrinsic laryngeal muscles

Extrinsic laryngeal muscles : 

2. Thyrohyoid Runs below omohyoid and sternohyoid muscles Origin - lateral thyroid lamina Course - upward Inserts - lower border of lateral hyoid bone Function - decreases distance between hyoid and thyroid; can depress larynx or elevate larynx Extrinsic laryngeal muscles

Extrinsic laryngeal muscles : 

3. Sternohyoid Origin - posterior manubrium and clavicle Courses - vertically Insert - body of hyoid Function – depressor pulls hyoid down Extrinsic laryngeal muscles

Extrinsic laryngeal muscles : 

4. Omohyoid Inferior belly Origin - scapula Course - horizontally Insert - intermediate tendon Superior belly Origin - intermediate tendon Courses - vertically Inserts - lower border of hyoid near greater horn Function – depresses hyoid Extrinsic laryngeal muscles

Extrinsic laryngeal muscles 5-Inferior pharyngeal constrictor : 

lowest portion of pharynx; part is entrance to esophagus -thyropharyngeus muscle **cricopharyngeous muscle - lowermost fibers of IPC = upper esophageal segment Origin - lateral thyroid and cricoid Course - posteriorly Insert - posteriorly at raphe formed when both sides meet at posterior pharyngeal wall creates a sphincter Function important during deglutition (swallowing) to move food down **cricopharyngeus portion relaxes to allow food to enter esophagus can help elevate larynx Extrinsic laryngeal muscles 5-Inferior pharyngeal constrictor

Slide 38: 

overall, #3-5 extrinsic muscles are closely intertwined and function to stabilize larynx in neck Inferior Pharyngeal Constrictor

Extrinsic Muscles: Suprahyoid : 

Extrinsic Muscles: Suprahyoid All function as laryngeal elevators with thyrohyoid many will also be mandibular depressors 6- Stylohyoid Origin - styloid process of the temporal bone Course - down and forward, parallel to posterior digastric Splits to pass the intermediate tendon of the digastric Inserts - on body of hyoid near greater horn Function - draws hyoid up and backward See prior slide

Extrinsic Muscles: Suprahyoid : 

7- Hyoglossus actually an extrinsic muscle of tongue Origin - hyoid greater horns and body Course - upward Inserts - posterior and lateral tongue Function - retracts tongue also can elevate hyoid/larynx Extrinsic Muscles: Suprahyoid

Extrinsic Muscles: Suprahyoid : 

8-Digastric Anterior belly - Origin - mandibular symphysis (antero-medial) Course - down and posteriorly Insert - lesser horn of hyoid Posterior belly Origin - mastoid process of temporal bone Course - down and anteriorly (deep to sternocleidomastoid) Insert - lesser horn of hyoid both bellies join by an intermediate tendon Function - elevates hyoid; or if hyoid fixed, depresses lower jaw Extrinsic Muscles: Suprahyoid

Extrinsic Muscles: Suprahyoid : 

9-Mylohyoid Forms muscular floor of mouth Origin - along inner surface of mandible Course - downward and medially Insert - midline raphe and body of hyoid Function - elevates hyoid, - on floor of mouth and tongue, i.e. has important role in initial stages of swallowing- - If hyoid bone fixed, may depress mandible Extrinsic Muscles: Suprahyoid

Extrinsic Muscles: Suprahyoid : 

10- Geniohyoid Origin - symphysis (inside center) of mandible Course - back and downward Insert - body of hyoid Function - pulls hyoid bone up and forward laryngeal elevator Extrinsic Muscles: Suprahyoid

Extrinsic Muscles: Suprahyoid : 

11-Genioglossus - also an extrinsic tongue muscle Origin - mandible symphysis Course - fan posteriorly Insert - lower fibers on body of hyoid, other fibers into tongue Function - may elevate hyoid; also moves tongue Extrinsic Muscles: Suprahyoid

Intrinsic muscles of larynx : 

Intrinsic muscles of larynx Supplied by CN X Two kinds of adjustments made by vocal folds: 1. Medial compression: extent to which vfs come to midline Adductor - bring arytenoids and vfs to midline Abductor - separate arytenoids and vocal folds 2. Longitudinal tension: degree of stretch on vfs Relaxer - shortens vocal folds Tensor - elongates and tightens vocal folds muscles always contract in symmetrical pairs on either side of larynx these two adjustments along with variable air supply provides variety of voice capabilities

Intrinsic muscles of larynx : 

12- Thyroarytenoid main muscle of vocal folds Composed of two muscle portions: Vocalis muscle - portion flanking vocal ligament Thyromuscularis - lateral portion 12a - Vocalis Origin - inner surface of thyroid cartilage angle Course - posteriorly Insert - vocal process of arytenoid cartilage Function – VF tensor – when functions with cricothyroid Intrinsic muscles of larynx

Slide 49: 

Thyrovocalis Thyromuscularis

Intrinsic muscles of larynx : 

12b- Thyromuscularis Origin – inner surface of thyroid angle – lateral to vocalis Course - posteriorly Insert - along base of arytenoid Function 1) relaxor when contracts alone – reduces tension along vfs 2) tensor - with other muscles of longitudinal tension also contracting helps increase vf tension 3) important for tight medial compression - adductor Intrinsic muscles of larynx

Intrinsic muscles of larynx : 

13-Superior thyroarytenoid not present in ½ of population Origin - upper thyroid angle near notch Courses - down and back along lateral surface of vocal fold Inserts - muscular process of arytenoid Function – relaxor; adduction tilts thyroid cartilage backward to relax vfs; also pulls muscular process forward leading to medial compression Intrinsic muscles of larynx

Intrinsic muscles of larynx : 

14- Posterior cricoarytenoid Origin - postero- medial cricoid lamina Courses - vertically Insert - muscular process of arytenoid Function – abductor Intrinsic muscles of larynx

Intrinsic muscles of larynx : 

15-Lateral cricoarytenoid Origin - cricoid arch (lateral cricoid) Course - back and upward Insert - muscular process and anterior surface of arytenoid Function – adductor rotates arytenoids bringing vocal process toward midline i.e. medial compression; also shapes glottis during whisper Intrinsic muscles of larynx

Intrinsic muscles of larynx : 

16- Oblique arytenoids Origin - muscular process and posterolateral surface of arytenoid Course - obliquely Insert - near apex of opposite arytenoid Function – adduction - approximates arytenoids so function in medial compression Intrinsic muscles of larynx

Intrinsic muscles of larynx : 

17- Transverse arytenoids Origin - lateral margin of arytenoid Course - horizontally Insert - lateral-posterior margin of opposite aryt Function – adduction - approximates aryts. by sliding them toward midline **posterior cricoarytenoids are antagonists of lateral cricoarytenoid and arytenoids Intrinsic muscles of larynx

Intrinsic muscles of larynx : 

19- Cricothyroid muscle Origin - anterolateral arch of cricoid Courses - fan vertically and posteriorly Inserts: - Pars oblique: I.e. lower fibers insert into inferior horn of thyroid - Pars recta Upper fibers insert into thyroid lamina Function: tensor - pars recta – pulls downward and reduces distance between cricoid and thyroid, thereby increasing the distance between thyroid and arytenoid and stretching the vocal fold inside placing them under tension - pars compacta – pulls forward, adding tension to vfs – key muscle for changing pitch Intrinsic muscles of larynx

Intrinsic muscles of larynx : 

18- Aryepiglottic muscle some fibers of oblique arytenoid course up to epiglottis may function in deglutition Intrinsic muscles of larynx

Review: intrinsic muscles : 

Review: intrinsic muscles Adductors – oblique & transverse arytenoids, lateral cricoarytenoids Abductor - posterior cricoarytenoids Tensor - cricothyroid; sometimes vocalis, thyromuscularis Relaxor - thyromuscularis, superior thyroarytenoids (if present)