Phonation Anatomy

what is phonation

- vocal fold vibration

- it's the source of voice for speech

where does phonation occur

- within the larynx

the larynx is _______ in the neck by the ______ bone

- suspended (aka held up)

- hyoid

the larynx is composed of

- cartilages

- muscles

- ligaments

- mucous membrane

larynx location

- adjacent toC4-C6

- on top of the trachea

length of larynx in female adults

- 3cm

length of larynx in male adults

- 4.4cm

biological functions of the larynx

- protects the lower respiratory tract / prevents food and liquid from entering trachea

- provides a stable framework (ex. lifting)

main function of the larynx

- to protect the airway so we don't die from aspiration

nonbiological functions of the larynx

- sound generator

the ______ and ______ are in close proximity of each other, so therefore there is a greater chance of aspiration

- trachea

- esophagus

6 laryngeal cartilages and the numbers of each

- 1 cricoid cartilage

- 1 thyroid cartilage

- 1 epiglottis

- 2 arytenoid cartilages

- 2 corniculate cartilages

- 2 cuneiform cartilages

where is the cricoid cartilage

- sits immediately above the trachea

- most inferior of laryngeal cartilages

what does the cricoid cartilage look like

- a ring

thyroid cartilage

- the largest laryngeal cartilage

common name for the thyroid notch

- adam's apple

where do the vocal folds attach?

- behind the thyroid notch

thyroid laminae

- 2 anterior plates

arytenoid cartilages

- paired cartilages

- in a pyramid shape

where are the arytenoid cartilages

- sits on top of the cricoid cartilage

where are the corniculate cartilages

- each one is on top of the arytenoid cartilages

corniculate cartilages

- landmarks in aryepiglottic folds

- paired

- provides rigidity to the folds

where are the cuneiform cartilages

- inside the aryepiglottic folds

- does NOT sit on top of any other cartilages

job of the cuneiform cartilages

- provides rigidity to the folds

where is the hyoid bone

- above and loosely articulates the thyroid cartilage

- underneath our chin

hyoid bone

- u-shaped

- only bone we discuss in relation to phonation

epiglottis

- leaf-like structure

- just below the thyroid notch (adam's apple)

what two structures are the epiglottis attached to

- hyoid bone

- thyroid cartilage

what ligament attaches the epiglottis to the hyoid bone

- hyoepiglottic ligament

what ligament attaches the epiglottis to the thyroid cartilage

- thyroepiglottic ligamnet

the epiglottis is joined at ______ cartilages via ________ folds

- arytenoid

- aryepiglottic folds

where do the vocal folds lie between?

- the arytenoid and thyroid cartilage

cricothyroid joint

- synovial joint (very mobile)

- can change vocal pitch

how do we change out pitch

- stretching our vocal folds

- moving forwards = making VF longer

where is the crycoarytenoid joint

- between the cricoid and arytenoid cartilages

crycoarytenoid joint

- synovial joints

- VF adduction

- changes vocal fold length

what 2 things are apart of the pharyngeal recesses

- vallecula

- pyriform sinuses

where is the vallecula

- space between the tongue and epiglottis

what does the vallecula have to do with swallowing

- when we eat or drink it passes this before going to the esophagus

patient who has swallowing difficulties and the vallecula

- after they swallow, we'll find residue sitting here

- the patient has to clear food out of this space or they pose a greater risk of aspiration

where is the pyriform sinuses

- space between the aryepiglottic fold and the thyroid cartilage

risks for the pyriform sinuses

- another pathway for food and liquid before it enters the esophagus (same as the vallecula)

which way do the vocal folds stretch?

- anteriorly to posteriorly

name all 5 vocal fold layers

- epithelial layer

- superficial lamina propria (SLP)

- intermediate lamina propria (ILP)

- deep lamina propria (DLP)

- thyroarytenoid muscle (aka vocalis muscle)

epithelial layer of the VF

- very top layer

- protective layer

- keeps VF moist and hydrated by retaining fluid

superficial lamina propria (SLP)

- made of elastin fiber so is very flexible

- can be extensively stretched

intermediate lamina propria (ILP)

- made of elastin fiber

- stretchable and elastic

deep lamina propria (DLP)

- made of collagen (thicker than other propria layers)

- supports the upper layers

thyroarytenoid muscle

- aka vocalis muscle

- makes up the bulk of the VF

what makes up the vocal ligament in the VF?

- intermediate lamina propria

- deep lamina propria

the top layers of the VF are _____, but as you go deeper the layers become more of a _____ role.

- stretchable and elastic

- supportive

why do we have so many layers of the VF?

- each layer has a different sound characteristic

- it makes us sound human!

- if we didn't have different layers, we'd sound like a robot

two parts of the laryngeal cavities

- aditus

- vestibule

aditus

- entryway from the larynx to the pharynx

- like a doorframe

vestibule

- space between entryway (aditus) and ventricular folds (false VF)

- space is compressed when we swallow

4 laryngeal cavities

- false VF

- rima vestibule

- laryngeal ventricle

- glottis

false VF

- aka ventricular folds

- not used for phonation, only in rare cases when they need to compensate

- not used during normal phonation

rima vestibule

- space between the false VF

laryngeal ventricle

- aka laryngeal sinus

- spaces between the true and false VF

glottis

- space between the true VF

- opens and closes to make voicing possible

laryngectomy

- removal of the whole larynx

- breathe through a hole in neck because it goes straight to their trachea

- cannot speak because VF is removed

2 kinds of laryngeal muscles

- intrinsic muscles

- extrinsic muscles

describe the intrinsic muscles

- both origin and insertion

- makes fine adjustments in the vocal mechanism (opening or closing VF)

describe the extrinsic muscles

- one attachment on a laryngeal cartilage and the other attachment on a non-laryngeal structure

- can lower or elevate the larynx

4 intrinsic laryngeal muscles

- abductors

- adductors

- tensors

- relaxers

abductors

- separate the VF

adductors

- brings VF together

tensors

- elongate/tighten VF

relaxers

- relax the VF

3 muscles of the adductors

- lateral cricoarytenoid (LCA)

- transverse arytenoid

- oblique arytenoid

1 muscle of the abdcutor

- posterior cricoarytenoid

lateral cricoarytenoid

- part of adductors

- attaches cricoid and muscular processes of arytenoids

transverse arytenoid

- part of adductors

- spans back surface of both arytenoid cartilages

- pulls the arytenoids together which brings the VF together

oblique arytenoid

- part of adductors

- connects at one arytenoid to the other

- sits right above (superficial) to the transverse arytenoid muscles

- pulls apex of the arytenoids medially (to the center)

posterior cricoarytenoid muscles (PCA)

- the one muscle of the abductor

- moves arytenoids out and abducts VF (opens glottis)

purpose of the addcutors

- to protect the airway and VF

- contracts to close the glottis

the 2 tensor muscles

cricothyroid

thyrovocalis

the one relaxer muscle

thyromuscularis

what are the two heads of the cricothyroid called

the pars recta

the pars oblique

primary muscle that we use to change vocal pitch and the primary tensor

cricothyroid

thyromuscularis

muscle mass lateral to the thyrovocalis

laryngeal elevators: list all muscles

Digastricus

Stylohyoid

Mylohyoid

Geniohyoid

Hyoglossus

Genioglossus

laryngeal depressors: list all muscles

Sternohyoid

Sternothyroid

Omohyoid

Thyrohyoid

suprahyoid

run from hyoid structure to structure ABOVE

infrahyoid

run from hyoid to structure BELOW

suprahyoid muscles are also known as

the laryngeal elevators

infrahyoid muscles are also known as

the laryngeal depressors

digastric muscle where and what it does

part of suprahyoid/elevator

anterior and posterior (2 muscle bellies)

elevates hyoid bone

very active when we are eating/drinking (more specifically chewing)

lowers the mandible OR elevates the larynx, depending on where the fixed point is

function of the stylohyoid

elevates and retracts the hyoid bone

part of suprahyoid/elevator

mylohyoid function and where

floor of the oral cavity

elevates hyoid bone, which in turn elevates the larynx

bottom most layer of muscle out of all the suprahyoid muscles

geniohyoid function and where

superior to mylohyoid

elevates and draw hyoid forward

genioglossus

tongue and muscle hyoid elevators

what does glossus mean

refers to tongue

hyoglossus

can do more than one thing function wise

from hyoid bone to tongue

can also be considered as a depressor depending where you look at

can be a laryngeal elevator or a tongue depressor

sternohyoid

depresses hyoid

from sternum to hyoid

omohyoid

depresses hyoid bone and larynx

from clavicle to hyoid bone

sternothyroid

depresses thyroid cartilage

from sternum to thyroid

thyrohyoid

depresses hyoid OR raises larynx

from thyroid to hyoid