Week Six Flashcards
Larynx: Extrinsic Parts & Endoscopy
How is the larynx positioned?
Suspended between the skull above and the bones of the torso below
What are the key connection points on the skull?
Styloid processes
Mastoid processes
What are the styloid processes?
Stylus shaped projections from the base of the skull, serving as the origin for several muscles
Located on the inner side of the jaw
What are the mastoid processes?
Larger, smoother protrusions behind the earlobes, providing insertion points for muscles
What is the hyoid bone?
Horseshoe-shaped bone that does not directly contact other bones
Suspended by a network of ligaments and muscles
What does the hyoid bone provide essential support for?
Only solid part of the tongue, offering critical structural support
Serves as an anchor for the larynx, facilitating speech and swallowing
What are the 3 projections of the hyoid bone?
Greater horn
Lesser horn
Body
What function does the sternum have for larynx suspension?
Manubrium acts as an anchor point for multiple muscles
What are the four extrinsic laryngeal muscle groups?
Pharyngeal constrictors
Infrahyoids
Suprahyoids
Pharyngeal elevators
What are pharyngeal constrictors?
Muscles that form the beck and side walls of the pharynx
Key for laryngeal support
What are the 3 types of pharyngeal constrictors?
Inferior pharyngeal constrictor (lowest)
Middle pharyngeal constrictor
Superior pharyngeal constrictor (highest)
Where does the inferior pharyngeal constrictor originate?
Originates are the sides of the cricoid and thyroid cartilages
Where does the inferior pharyngeal constrictor insert?
Inserts into the median raphe of the pharynx
What is the function of the inferior pharyngeal constrictor?
Pulls the larynx backward and upward (diagonally) when contracted and narrows the laryngopharynx (lower part of the pharynx
Where does the middle pharyngeal constrictor originate?
Originates from the greater and lesser horns of the hyoid bone and stylohyoid ligament
Where does the middle pharyngeal constrictor insert?
Inserts into the median raphe of the pharynx
What is the function of the middle pharyngeal constrictor?
Retracts and elevates the hyoid bone, narrowing the oropharynx
Useful for ejectives
What are the infrahyoid muscles?
Strap muscles
Crucial for forced inspiration and phonation
Connect to the hyoid bone from beneath
Innervated from C1-C3
What are the 4 main strap muscles?
Sternohyoid
Sternothyroid
Thyrohyoid
Omohyoid
Where does the sternohyoid muscle originate?
Manubrium of the sternum
Where does the sternohyoid muscle insert?
Hyoid bone
What is the function of the sternohyoid muscle?
Contraction will lower the hyoid bone, linking the sternum to the hyoid
Where does the thyrohyoid muscle originate?
Thyroid cartilage
Where does the thryohyoid muscle insert?
Hyoid bone
What is the function of the thyrohyoid
Modulates tension between the thyroid and hyoid, if hyoid is stable it will raise the larynx but if larynx is stable it will lower hyoid
Where does the sternothyroid muscle originate?
Manubrium of sternum
Where does the sternothyroid muscle insert?
Thyroid cartilage
What is the function of the sternothyroid?
Lowers the larynx by connecting the sternum to the thyroid
What are the two bellies of the omohyoid?
Superior
Inferior
Joined by tendon that attaches to clavicle
Where do the omohyoid bellies originate?
Inferior: superior border of scapula
Superior: intermediate tendon
Where do the omohyoid bellies insert?
Inferior: intermediate tendon
Superior: body of hyoid bone
What is the function of the omohyoid muscle?
Has two segments. lowers or stabilizes the hyoid bone, and indirectly affects larynx position
What are the suprahyoid muscles?
Located above the hyoid bone
Function to elevate the hyoid bone, and consequently, the larynx, facilitating swallowing and affecting pitch
What are the four suprahyoid muscles?
Digastric
Stylohyoid
Mylohyoid
Geniohyoid
Where does the digastric muscle originate?
Anterior belly: connected to the digastric fossa (ditch) of mandible (inside of jaw)
Posterior belly: to the mastoid process (behind the ear)
What is the function of the digastric muscle?
Two-bellied muscle contributing to jaw opening and larynx elevation
Where does the stylohyoid muscle originate?
Running parallel to the posterior belly of the digrastric
Originates from the styloid process
Where does the stylohyoid muscle insert?
Inserts into hyoid
What is the function of the stylohyoid muscle?
Raise and retract the hyoid bone
Where does the mylohyoid muscle originate?
Thin, flat muscle forming the floor of the mouth
Originates from the mylohyoid line of the mandible
Where does the mylohyoid insert?
Inserts into the hyoid bone
What is the function of the mylohyoid muscle?
Raises the hyoid and assists in elevating the tongue during swallowing
Muscles look like a leaf
Deeper
Where does the geniohyoid muscle originate?
Narrow muscle running above the mylohyoid
Originates from the mental spines of the mandible
Where does the geniohyoid muscle insert?
Inserts into the hyoid bone
What is the function of the geniohyoid muscle?
Elevates the hyoid, shortens the floor of the mouth, aids in swallowing
What are pharyngeal elevators?
Muscles that raise the larynx and pharyngeal walls
What are the 3 pharyngeal elevators?
Stylopharyngeus
Palatopharyngeus
Salpingopharyngeus
Where does the stylopharyngeus muscle originate?
The superior styloid process
Where does the stylopharyngess muscle insert?
Inferior side of the pharyngeal wall and thyroid cartilage
What is the function of the stylopharyngeus muscle?
Elevates the larynx and widens the pharynx
Where does the palatopharyngeus muscle originate?
In the soft palate merging with the stylopharyngeus
Where does the palatopharyngeus insert?
Thyroid cartilage
What is the function of the palatopharyngeus?
Raises the larynx and helps in lowering the velum for velic sounds
Where does the salpingopharyngeus muscle originate?
Eustachian tube opening
Where does the salpingopharyngeus muscle insert?
Palatopharyngeus muscle
What is the function of the salpingopharyngeus muscle?
Elevating the larynx and pharynx
Equalizing pressure between outer and middle ear
What is breathy voice characterized by?
Combination of phonation and frication of air at the glottis
What are the two main ways breathy voice is produced?
Less contraction of LCA muscles, leaving a longitudinal gap
Inadequate contraction of IA muscles leaving a posterior gap
What are some characteristics of breathy voice?
Vocal folds do not fully close, affecting resonance and volume
Quieter than modal voice
Requires more air, faster respiration or shorter phrases
What is creaky voice characterized by?
Significantly lower fundamental frequency
How is creaky voice produced?
Vocal folds are shortened and slackened
IA muscles draw arytenoid cartilages together, allowing long closure periods
Tiny bursts of air escape between closures
What are some characteristics of creaky voice?
Longer phonation cycles
F0 is damped
Very little air escapes, energy efficient
What are the two types of non-pulmonic airstreams?
Glottalic ingressives (implosives)
Glottalic egressive (ejectives)
What is the mechanism for implosives?
Draw the larynx downward creating a pressure difference
Voiced
How are implosives produced?
Lowering the larynx, expands the upper vocal tract
Lowering the tongue or jaw can facilitate implosive production
How are ejectives produced?
Start with closed larynx and oral constriction, then raise the larynx to pressure air
Release of the oral constriction produces a popping sound
What muscles are used to produce an ejective?
Suprahyoid and pharyngeal elevator muscles
What is endoscopy?
Relatively invasive
Examine the interior surfaces of an organ or tissue
Why is endoscopy useful in voice studies?
Visual structure and movement of vocal folds
Diagnose pathologies affecting voice quality
Assess effectiveness of vocal treatment
What are the types of endoscopy?
Rigid endoscopy
Flexible endoscopy
What is a rigid endoscopy used for?
Provides high quality images, used for stationary observations
What is a flexible endoscopy used for?
Allows for dynamic assessment, suitable for observing vocal fold during speech or singing
How does endoscopy work?
Light is transmitted to illuminate vocal folds
Camera is attached to capture real-time video/images
What is a stroboscopic endoscopy?
Capture slow-motion images of vocal fold vibration
