Velopharyngeal-Nasal Apparatus Anatomy

Velopharyngeal-Nasal Apparatus

• Skeletal superstructure includes the first six cervical vertebrae and skull bones
• Skull bones include the cranium and facial complex consisting of the forehead, eyes, nose, mouth, and upper throat

Nasopharynx

• Lies behind the nose and above the velum
• Houses the Eustachian tube, with at least one end in the middle ear
• Connects to the nasal cavity through the nasal conchae

Velum

• A flap made of the soft palate and uvula
• Structure hangs like a pendulum in the back of the mouth
• Structural composition includes 2 glandular tissues, 1 muscle, and 1 tendon

Nasal Cavities

• Located behind the outer nose
• Consist of 2 chambers running side by side, separated by the nasal septum
• Nasal conchae are the most complex formations and are likened to conch shells with cul-de-sacs

Outer Nose

• Ala equals nostral and plays a role in the degree of coupling between the nasal cavity and atmosphere

Forces and Movements

• Passive forces include gravity, muscle recoil, and surface tension
• Active forces include the muscles of the pharynx

Muscles of Pharynx

• Constrictors include the Superior, Middle and Inferior Pharygeus, Salpingopharyngeus, Stylopharyngeus, and Palatopharyngeus

Muscles of Velum

• Influence structure positioning, configuration, and mechanical status

Elevators, Depressors, and Tensor Muscles

• There are 2 elevators, 2 depressors, and 1 tensor
• Elevators: Palatal Levator and Uvulus
• Depressors: Glossopalatine and Pharyngopalatine
• Tensor: Palatal Tenor

Muscles of Outer Nose

• Can be used to help convey meaning
• Influence velopharyngeal-nasal function

Muscles of Outer Nose

• Elevators: Levator Labii Superioris Alaeque Nasi
• Depressors: Nasalis, Depressor Alae Nasi (Flora’s fav)
• Dilators: Anterior Nasal Dilator and Posterior Nasal Dilator

Movements of Velopharyngeal-Nasal Apparatus: Velum

• When relaxed, it hangs in the back of the mouth
• When contracted, it moves upward and backward, forming a hook-like shape which closes the valve
• When relaxed after contraction, it moves downward and forward, thus opening the valve back up

Movements of Outer Nose

• Movements are generally very small and barely noticeable
• Movements are more pronounced when breathing after exertion (high drive) or when signaling contempt or disdain
• Nostrils will flare in these instances

Coupling Between Oral and Nasal Cavities

• The velopharyngeal port is the space between the velum and back of the nose
• Most of the time the velopharyngeal port is open
• The velum contracts using muscular force by the elevators & tensors, closing the port
• This occurs when talking and swallowing
• When the velum is closed, the oral and nasal cavities are decoupled, and air flows out the mouth
• The port is open during passive recoil force & active forces of the velum depressors.
• The oral and nasal cavities are coupled, and air flows through the nose in this instance

Coupling Between Nasal Cavities and Atmosphere

• Is influenced by size changes of the nostrils
• Nostrils will remain open the majority of the time
• Other factors include a stuffed up nose (sick), trauma, and cleft lip with nostril involvement

Three Control Variables of Velopharyngeal-Nasal Function

Airway Resistance

• Opposition to airflow through structures of the velopharyngeal nasal airway
• Influenced by adjustments of size & configuration of the velopharyngeal port, nasal cavities, and outer nose as well as degree of coupling.
• It is air flow dependent: increase in airflow equals an increase in resistance

Sphincter Compression

• Refers to the force of closure of the velopharyngeal-nasal apparatus (port)
• The muscular pressure to close must exceed the airflow from the pharyngeal system
• Depends on the amount of air pressure
• Helps direct where the air flow goes
• Muscular pressure will need to increase when increasing the amount of air pressure.

Acoustic Impedance

• Opposition to airflow that is frequency specific
• Size of the velopharyngeal port determines how sound energy is divided between the oral & nasal cavities
• If VP is closed, all sound is directed to the oral cavity
• If VP is open, some sound will go through the nasal cavity impacting the amount of sound energy released

Neural Substrates

• Pharynx: Motor nerves are IX, X, XI; Sensory nerves are V, VII, X
• Velum: Nerves are IX, X, XI (bundle of nerves - pharyngeal plexus), V, VII [possible], & X
• Outer Nose: VII & V

Ventilation

• Movement of air in & out of the pulmonary apparatus for gas exchange
• Nasal breathing is less efficient but more beneficial than mouth breathing
• Resting tidal breathing typically occurs through the nose

Benefits of Nasal Breathing

• Moistens the air
• Warms air
• Filters air
• Provides adequate time for gas exchange to occur

Nasal Valve Modulation

• The nose is a major source of resistance
• Major source of resistance is towards the front ends of the nasal passage
• Nasal patency is how easily air can move in and out of the nose
• Nasal patency is influenced by trauma, infection, temperature changes, and spicy food
• The greatest resistance to airflow occurs at the 2 front ends (nasal valves)

Nasal Valves

• Internal: Account for 2/3 of airway resistance and are the main regulators for nasal air flow, are active during tidal breathing, larger during inspiration, and smaller during expiration
• External: Only dilate or constrict the nasal valves; i.e. flare nostrils

Nasal Cycling

• When the nasal passages are behaving independently
• Passages cycle through shrinking and swelling, one side shrinks while the other swells

Nasal-Oral Switching

• Nasal breathing is more desirable even though it is less efficient
• Constant mouth breathing does not provide the same benefits as nose breathing
• Only 10% of breathing is through the mouth
• Governs patency

Mouth Breathing

• Mouth breathing occurs during a higher need for oxygen, when talking, or when the nose is stuffed
• We switch from nasal to mouth breathing before we are consciously aware that we need to switch and when nose breathing is not sufficient

Velopharyngeal-Nasal Function in Speech Production

• Role is to control the degree of coupling between oral & nasal cavities and the nasal cavity & atmosphere

Sustained Utterances

• Prolonged vowel and consonant productions are typically produced with specific configurations of velopharyngeal-nasal apparatus
• Sustained utterance (vowel /a/) goes beyond tidal breathing
• Relatively stable configuration of velopharyngeal-nasal apparatus
• The velum is raised up & back during vowel production
• Compression of the velopharyngeal sphincter would be increased when the velum is contracted more due to greater air pressure and increasing intensity of volume

Outer Nose Muscles

• Active during sustained utterances, as they help control the air pressures and flows, with size, shape, and stiffness of the nasal cavities
• Movements of the outer nose are negligible, so it is not considered an articulator

Running Speech Activities

• Require rapid movement; precise patterns
• Multiple speech sounds require fluid change of speech streams
• Takes into account the rate of speech sounds so faster speech requires faster adjustments to the apparatus
• For nasal and consonant speech sounds

Velopharynx As Articulator Contention

• Argument for: It moves in accordance with the production of different speech sounds
• Argument against: It is always considered on when you're speaking and moves regardless, and is off when you’re done speaking
• Velopharyngeal apparatus plays an important role during inspiration for running speech activities
• During running speech and when taking a break from speaking to breathe, you breathe quickly through mouth and nose
• Simultaneousness allows maintenance of fluency during these activities

Development of Velopharyngeal-Nasal Function

• At birth, the larynx is located high in the neck, so the velum and epiglottis are approximated
• As the child ages, the nasopharyngeal tonsils grow then shrink
• Approximation between the velum and pharynx lengthens as growth continues
• Ear infections are more common during this time given these factors
• Eustachian tube becomes more vertical around age 8, and ear infections are subsequently less likely

Velopharyngeal-Nasal Function by Age/Gender

• Age-related changes: change in size, but this is not clinically relevant
• An advanced aged has no affect in functionality of velopharyngeal-nasal
• Gender difference in velopharyngeal-nasal: Regardless of gender assignments, differences are not clinically relevant

Velopharyngeal-Nasal Disorders and Speech Production

• Primarily concerned with organic disorders congenital, developmental, or acquired
• Congenital: Cleft lip &/or palate, and submucous cleft that looks like the roof of the mouth is in tact and is have a bluish color.
• Acquired: Issues with complete seal for nasal sounds

Congenital Disorders

• Cleft lip &/or palate: Can be complete, going up into the nasal cavity or incomplete, not yet reaching the nose and can be unilateral or bilateral

Acquired Disorder

• Trauma &/or surgeries or structural disease

Neuromotor Disorders

• Paresis or paralysis of velum
• Cerebral Palsy, TBI, stroke, MS, etc influence muscle contraction which impacts velum movement