Clinical Anatomy of Speech and Swallow Flashcards
What does swallowing require?
Efficient and synchronised motor control
What are the three phases of swallowing?
Oral phase (voluntary), pharyngeal phase (involuntary), oesophageal phase (involuntary)
What occurs in the oral phase?
Mastication, bolus manipulation, labial seal
What occurs in the pharyngeal phase?
Hyolaryngeal elevation, sequential constrictor contraction
What occurs in the oesophageal phase?
Relaxation of the upper oesophageal sphincter (cricopharyngeal)
What nerve innervates the muscles of mastication?
CN V3
What is the role of the muscles of mastication in the oral phase of swallowing?
Break down food and allow it to mix with saliva
What is the involvement of the facial muscles in the oral phase of swallowing?
Create labial seal = orbicularis oris
Tightens cheek = buccinator
What nerve innervates the facial muscles involved in the oral phase of swallowing?
CN VII
What structures manipulate the bolus when it is in the oral cavity?
The intrinsic and extrinsic tongue muscles (CN XII) = manipulate bolus and align it between the dentition and push it against the hard palate
What does the soft palate do during the oral phase of swallowing?
Depresses to create an oropharyngeal seal = tongue also ripples bolus posteriorly
What nerve innervates the soft palate?
CN X = lesser palatine nerve
What nerves innervate the hard palate?
Branches of pterygopalatine ganglion = greater palatine nerve
What kind of modalities are supplied to the hard palate?
Secretomotor from CN VII, general sensation from CN V2
What structure do the nerves supplying the hard palate pass through?
Palatine canal
Where does the incisive branch of the nasopalatine nerve supply?
The area of the hard palate behind the front teeth
What covers the palatal rugae?
Mucosa = keratinised stratified squamous epithelium
What extrinsic muscles of the tongue does the facial nerve supply somatic innervation to?
Genioglossus, hyoglossus and styloglossus
What is the course of the facial nerve into the mouth?
Extends from medulla and passes through hypoglossal canal = descends close to carotid sheath, courses lateral to hyoglossus into floor of mouth
What initiates the pharyngeal phase of swallowing?
Delivery of the bolus to the oropharynx
What is the critical step in the pharyngeal phase of swallowing?
Switch from air channel to food channel (<1s)
What are the facilitators of the pharyngeal phase of swallowing?
Elevation of soft palate
Posterior pressure from tongue
Hyolaryngeal elevation
Pharyngeal constrictor contraction
What does the elevation of the soft palate during the pharyngeal phase cause?
Seals off the nasopharynx from the oropharynx
What does the posterior pressure from the tongue help during the pharyngeal phase?
Seals of laryngeal aditus = aided by epiglottis
What is the purpose of the hyolaryngeal elevation during the pharyngeal phase?
Protects airway and opens upper oesophageal sphincter
What muscles elevate the hyoid bone?
Suprahyoid and longitudinal pharyngeal muscles drag the hyoid bone superiorly and anteriorly
What is the elevation of the hyoid bone coupled with?
Posterior tongue pressure from the stylohyoid and hyoglossus
What does the elevation of the hyoid bone cause the epiglottis to do?
Forces epiglottis inferior to the tongue and covers the laryngeal aditus to protect the airway
What aids the movement of the bolus from the laryngopharynx to the oesophagus?
Tongue pressure, sequential contraction of pharyngeal constrictors (superior to inferior), relaxation of upper oesophageal sphincter (cricopharyngeus)
How long does the oesophageal phase last?
8-20s
When does the oesophageal phase begin?
Once the cricopharyngeal sphincter has opened = bolus is then passed to the stomach via peristaltic action
What nerve innervates the cricopharyngeus?
External laryngeal nerve (CN X)
What does the retropharyngeal space communicate with?
The mediastinum = allows spread of infection
What may be the symptoms of a parapharyngeal space tumour?
May be asymptomatic for some time = can present with symptoms of lower cranial nerve dysfunction
Where does the pharyngeal plexus supply?
Muscles of soft palate and pharynx (except tensor veli palatine), sensory component of mucosa
What cranial nerves make up the pharyngeal plexus?
CN IX and X
What is the sensory component of the gag reflex?
Stimuli present to posterior 1/3 of tongue, palatine tonsils and wall of oropharynx = innervated by CN IX
What is the aim of the motor component of the gag reflex?
Tries to close off the oropharynx by muscular contraction
What makes up the motor component of the gag reflex?
Constrictors of pharynx (CN X), longitudinal muscles of pharynx (CN IX and X), tongue (CN XII), soft palate (CN X)
What are the gateways to the mouth and tonsillar bed?
The gaps between the superior and inferior pharyngeal constrictor muscles
What do the gateways to the mouth and tonsillar bed allow?
Passage of CN IX, lingual artery and stylopharyngeus muscle
What nerve may be damaged in a tonsillectomy?
CN IX
What is the fundamental function of the larynx?
A sphincter = carries out airflow regulation and protection
What happens to the vocal cords during forced expiration?
They abducts to allow passage of air
What muscles causes the widening of the rima glottidis?
Contraction of the posterior crico-arytenoid muscles = causes lateral rotation of the crico-artytenoid joint
How does the larynx carry out a protective role?
Through glottic closure and the cough reflex
When is the rima glottidis closed firmly?
During swallowing to reduce passage of substances other than air into the lower respiratory tract
What happens to the diaphragm and intercostal muscles during inspiration?
They contract and pull downwards
What occurs during controlled expiration?
Contraction of the inspiratory muscles = helps build pressure in respiratory tree inferior to larynx (subglottal pressure)
What does the pressure needed for phonation depend on?
Depends on the vocal task
What must be adequate for phonation to occur?
Subglottal pressure threshold must be reached = Air crosses vocal cords causing vibration
What dictates the pitch of the voice?
The length/tension of the vocal cords
What kind of muscles are the intrinsic laryngeal muscles?
Skeletal = involuntary
What effect does vocal cord tension have on vocal pitch?
Tension increase pitch, relaxation decreases pitch
What effect does abduction and adduction of the vocal cords have on the volume of the voice?
Adduction makes the voice quieter, abduction makes the voice louder
What nerve innervates the intrinsic muscles of the larynx?
All innervated by the inferior laryngeal branch of CN X (except cricothyroid)
What is the function of the thyro-arytenoid muscle?
Relaxes vocal ligaments = decreases pitch
Where is the thyro-arytenoid muscle located?
Attaches to posterior thyroid to anterior arytenoid cartilage
What is the function of the cricothyroid muscle?
Tenses vocal ligaments = increase pitch
Nods thyroid cartilage
Where is the cricothyroid muscle located?
Attaches to anterolateral cricoid cartilage to inferior horn of thyroid cartilage
What is the normal state of the laryngeal muscles?
They are relaxed
Which larynx muscles contract during forced expiration?
The posterior crico-arytenoid muscle = vocal cords
Which muscle aid the lateral crico-arytenoid muscles in adducting the vocal cords during phonation?
Arytenoid muscle
Which nerve supplies the mucosa of the larynx above the vocal folds?
Internal laryngeal nerve = branch of superior laryngeal nerve
Which nerve supplies the mucosa of the larynx under below the vocal cords?
Inferior laryngeal nerve
Where does the left recurrent laryngeal nerve become the inferior laryngeal nerve?
At the level of the cricothyroid joint
Which nerve gives rise to the superior laryngeal nerve?
The vagus nerve = passes through jugular foramen to give superior laryngeal branch
What structure does the vagus nerve descend through the neck in?
The carotid sheath
Where does the recurrent laryngeal nerve branch off from the vagus nerve?
Branches off in the mediastinum
What nerves connect in Galen’s anastomosis?
Internal laryngeal nerve (superior laryngeal nerve) and the recurrent laryngeal nerve
What kind of reflex is the cough reflex?
It is involuntary
Where are the sensory stimuli for the cough reflex detected?
Sensory stimuli in the supraglottis = then conveyed to the brainstem via the internal laryngeal nerve
What occurs during the cough reflex once the sensory information has reached the brainstem?
Vocal cords contract to shut larynx and glottis closes to increase body cavity pressure = glottic release of high pressure air jet
What modalities does the vagus nerve supply the pharynx, palate and larynx with?
Sensory and motor supply
How do you test the function of the vagus nerve in the pharynx?
Ask patient to swallow = watch larynx move up and down, do they splutter?
How do you test the function of the vagus nerve in the larynx?
Listen to the patient speak = is the voice hoarse?
How may the function of the vagus nerve in the throat be tested?
Ask the patient to cough = is the cough normal and powerful?
What is dysphonia?
Impaired ability to produce an appropriate level of phonation
What are some causes of dysphonia?
Neoplasm, neuromuscular dysfunction, inflammation
Where do supraglottic tumours drain lymph to?
The superior deep cervical lymph nodes
Where do most glottic tumours form?
Present on the vocal cords = 95% stay on cords
How do glottic and subglottic tumours present?
Voice change and airway obstruction
Where can subglottic tumours spread to?
Paratracheal nodes
Why does the sound produced in the larynx need to be amplified?
Larynx is insufficient to produce loud sound
What shape is the pathway between the larynx and mouth that vocal sounds are transmitted through?
It is funnel shaped
What structures amplify the vocal “buzz” produced by the larynx?
Pharynx, oral cavity, nasal cavity
How are oral sounds produced?
Soft palate tenses (CN V3) and elevates (CN X) to close off the entrance to the nasopharynx = directs stream of air through oral cavity
How are vowels and consonants produced?
Sound interrupted by tongue (CN XII) and teeth/lips (CN VII) to produce most vowels/consonants
How are nasal sounds produced?
Soft palate tenses (CN V3) and descends (CN X) to close off entrance into oropharynx = directs stream of air through nasal cavities
What are the three nasal sounds that can be produced?
m, n and ing = depends on position of tongue (CN XII), teeth and lips (CN VII)
What are the muscles of the soft palate?
Tensor veli palatini, levator veli palatini, palatoglossus, palatopharyngeus, uvular
What is the action of tensor veli palatini?
Tenses soft palate and opens Eustachian tube during swallowing
What is the function of levator veli palatini?
Elevates soft palate during swallowing
What does the palatoglossus muscle do?
Elevates posterior part of tongue and draws soft palate onto tongue
What is the function of the palatopharyngeus muscle?
Tenses soft palate and pulls walls of pharynx superiorly/anteriorly/medically during swallowing
