Nasopharynx, Oropharynx and Laryngopharynx Flashcards
What structures form the roof of the mouth?
Alveolar arches
Palatine process of maxilla
Horizontal process of palatine bone
What muscle forms the floor of the mouth?
Mylohyoid
What secondary muscles contribute to the floor of the mouth? Are they located inferiorly or superiorly to the mylohyoid?
Digastric muscle (inferior) Geniohyoid (superior)
What are the 3 main kinds of papillae found on the tongue? Where are they located?
Valate papillae (anterior to sulcus terminalis) Folate papillae (along the sides of the tongue) Fungiform papillae (over the tongue's surface)
What is the foramen caecum?
A depression behind the sulcus terminalis on the tongue, remnant of a duct from which the thyroid develops
How does the thyroid develop?
As a diverticulum from the oropharynx
Why is the surface of the tongue posterior to the sulcus terminalis “bumpy”?
Mucosa overlies lymphoid nodules
List the 4 extrinsic muscles of the tongue and their respective origins and primary actions
Styloglossus (styloid process of temporal bone; elevation; retraction)
Palatoglossus (posterior palate; elevation)
Genioglossus (back of the mandible in the midline; protrusion)
Hyoglossus (hyoid bone; depression)
Which nerve innervates the extrinsic muscles of the tongue?
CNXII, except for palatoglossus which is innervated by the pharyngeal branch of CNX
List the 4 intrinsic muscles of the tongue
Superior longitudinal
Inferior longitudinal
Transverse
Cervical
Contrast the roles of the extrinsic and intrinsic muscles of the tongue
Extrinsic: change the position of the tongue
Intrinsic: change the shape of the tongue
Which nerve innervates the intrinsic muscles of the tongue?
CNXII
What nerve provides general sensory innervation to the tongue?
Lingual nerve (branch of the mandibular division of CNV) to anterior 2/3 CNIX to posterior 1/3
What nerve provides special sensory innervation to the tongue?
Chorda tympani (branch of CNVII) to anterior 2/3
CNIX to posterior 1/3
Internal laryngeal to the base of the tongue
Which nerve forms the afferent arc of the gag reflex?
CNIX
Provide a breakdown of the different types of teeth in the adult mouth (for one set only i.e. upper or lower)
2 medial and 2 lateral incisors
2 canines
4 premolars
6 molars (including 2 wisdom teeth)
Which nerves supply the teeth?
Superior alveolar nerve to upper teeth
Inferior alveolar nerve to lower teeth
What is the inferior alveolar nerve a branch of?
The mandibular division of CNV
Describe the course of the inferior alveolar nerve
Travels through the mandibular foramen and through the mandible to supply the lower teeth
What are the superior alveolar nerves a branch of?
The maxillary division of CNV
What structure(s) do the superior alveolar nerves refer pain from/to?
Maxillary sinuses, structures near the midline face
What structure(s) does the inferior alveolar nerve refer pain from/to?
External auditory meatus (via the auriculotemporal nerve)
List the 3 salivary glands
Parotid
Sublingual
Submandibular
Where does the duct from the parotid gland open into the mouth?
In the vestibule between the lip and the gum opposite the 2nd molar
What are the 2 parts of the submandibular gland?
Inferior part: inferior to mylohyoid, outside the oral cavity
Superior part: superior to mylohyoid, inside the oral cavity
What is the structural relationship between the submandibular gland and the mylohyoid muscle?
Mylohyoid separates the submandibular gland into 2 parts
Submandibular gland wraps around the free posterior edge of mylohyoid
What is the clinical importance of the lingual vasculature?
Important for absorptions of drugs administered sublingually (e.g. GTNs)
Which muscles form the 2 arches separating the oral cavity from the oropharynx?
Palatoglossus (palatoglossal arch; more anterior)
Palatopharyngeus (palatopharyngeal arch; more posterior)
What structure lies between the 2 arches at the back of the oral cavity?
Palatine tonsil
What do palatoglossus and palatopharyngeus do?
Elevate structures of the oral cavity/oropharynx
What structures form the soft palate?
Musculus uvulae (hangs down in the midline, forming the uvula) Palatine aponeurosis (connects the horizontal plate of the palatine bone to the musculus uvulae)
Where are the palatine glands located?
In the lining of the hard and soft palates
List the 5 muscles which support the structure of the soft palate and allow it to move. In which direction does each move the palate?
Tensor veli palatini (elevates to seal off nasal cavity)
Levator veli palatini (elevates to seal off nasal cavity)
Musculus uvulae
Palatoglossus (depresses to seal off oral cavity)
Palatopharyngeus (depresses to seal off oral cavity)
Which nerve innervates the muscles supporting the soft palate?
Pharyngeal branches of CNX, except tensor veli palatini which is innervated by CNV
What is the secondary role of tensor veli palatini and levator veli palatini?
Can change the dimensions of the auditory tube, equalising the pressure in the middle ear
What are the 2 main roles of the soft palate?
To seal the nasal cavity during swallowing, coughing and suctioning
To seal the oral cavity to allow unimpeded breathing during chewing
What lymphoid tissues form Waldeyer’s ring?
Pharyngeal
Tubal
Palatine
Lingual
What structures form the superior and inferior margins of the larynx?
Begins at level of epiglottis
Ends at C6/lower border of cricoid cartilage
Describe the major structures of the anterior larynx, in order of most superior to most inferior
Epiglottic cartilage Hyoid bone Thyrohyoid membrane Thyroid cartilage Cricothyroid membrane Cricoid cartilage
Which laryngeal structure is known colloquially as the Adam’s apple in males? What is the reason for the difference in shape between females and males?
Thyroid cartilage; develops under influence of the sex hormones
What is the main structural difference between the thyroid and cricoid cartilages?
Thyroid cartilage is open posteriorly to form the laryngeal inlet
Cricoid cartilage is a continuous ring, with a tall lamina posteriorly
What are the 2 movements of the arytenoid cartilages?
Swivel down through central axis (to adduct or abduct the vocal cords)
Slide together
What are the 2 processes of the arytenoid cartilages?
Vocal process
Muscular process
What does the cricoid cartilage articulate with?
The inferior horn of the thyroid cartilage
Describe the structure of the laryngeal membranes
Not completely continuous; contain deficiencies for nerves and vessels
Where are the vocal ligaments located?
From the vocal processes of the arytenoid cartilages to the posterior aspect of the thyroid cartilage
What are the 2 sets of vocal ligaments called?
Vestibular fold (false vocal cords) Vocal fold (true vocal cords)
What movements of the vocal cords are required for phonation and inspiration respectively?
Adduction for phonation
Abduction for inspiration
List the 7 intrinsic muscles of the larynx
Posterior cricoarytenoid Transverse arytenoid Oblique arytenoids Lateral cricoarytenoid Cricothyroid Thyroarytenoid Vocalis
What is the primary action of posterior cricoarytenoid?
Abducts vocal fold
What is the primary action of the transverse and oblique arytenoids?
Closes rima glottis
What is the primary action of lateral cricoarytenoid?
Adducts vocal fold
What is the primary action of cricothyroid?
Lengthens vocal fold (for high-pitched sounds)
What is the primary action of vocalis and thyroarytenoid?
Relaxes vocal fold
Describe the innervation of the larynx
CNX gives off the superior laryngeal and recurrent laryngeal
Superior laryngeal gives off the internal laryngeal (which breaks through a hole in the thyrohyroid membrane to provide sensory innervation to the mucosa above the vocal cords) and the external laryngeal (which innervates the cricothyroid)
Recurrent laryngeal supplies all the other intrinsic laryngeal muscles and provides sensory innervation to the mucosa below the vocal folds
What is the result of a lesion to the external laryngeal nerve?
Difficulty with higher pitched sounds and changing vocal pitch (due to palsy of the cricothyroid muscle, responsible for lengthening the vocal cords)
What is the result of a lesion to the recurrent laryngeal nerve? When might this occur?
Hoarse voice and stridor (can’t fully adduct vocal ligaments)
May be damaged when repairing a patent ductus arteriosus
List the 3 main vessels supply the larynx
Superior thyroid vessels
Superior laryngeal vessels (run with internal laryngeal nerve)
Inferior thyroid vein
Where is the inferior thyroid vein located? Why is this clinically significant?
Directly over the anterior trachea in the midline; this puts it at risk when performing an emergency tracheotomy; if it ruptures, it will bleed into the airways and the patient may drown
How should a cricothyroid membrane puncture be performed?
Enter the larynx at the level of the cricothyroid membrane and at a slightly downward angle to avoid the vocal ligaments
What is the role of the epiglottic vallecula?
Space between the back of the tongue and epiglottis where a food bolus sits and pushes the epiglottis back to seal off the airways
What is the role of the piriform recesses?
Act as channels for the passage of liquid into the oesophagus as fluid cannot push the epiglottis down to seal off the airway
How is the airway sealed during eating?
The epiglottis is pushed back over the larynx by the bolus of food, the larynx moves to help seal the inlet and contraction of the laryngeal muscles occurs to tighten up the edges
What forms the lateral boundaries of the laryngeal inlet?
The aryepiglottic folds
List the 6 pharyngeal muscles
Salpingopharynx Palatopharyngeus Superior constrictor Stylopharyngeus Middle constrictor Inferior constrictor
What nerve (and nucleus) supplies the muscles of the pharynx?
CNX via nucleus ambiguus, except for stylopharyngeus which is innervated by CNIX
List the 8 steps involved in swallowing/deglutition
- Bolus shaped and pushes by tongue to palate
- Soft palate descends and palatal arches are approximated to grip and push the bolus into the oropharynx
- Soft palate elevated and tightened to prevent bolus entering nasal cavity
- Larynx and pharynx elevated to bring bolus closer to oesophagus
- Laryngeal inlet closed to prevent bolus from entering the trachea
- Bolus is pushed down the oropharynx and over the epiglottis
- Bolus forced down through laryngopharynx and into oesophagus
- Larynx depressed to return to normal position (mainly due to elastic recoil)
