Session 5: The Airway and its Relations Flashcards
What type of epithelium lines the conchae?
Respiratory Epithelium
Increases SA for warming + humidifying inspired air + traps pathogens
(conchae AKA turbinate bones)
What name is given to the gaps between conchae?
Meati (superior, middle, inferior)
What is the name of the space superior to the superior concha?
Sphenoethmoidal Recess
Which sinus drains into the sphenoethmoidal recess?
Sphenoidal Sinus
What action does the epiglottis perform to close off the laryngeal inlet?
Retroflexion
What is the role of the pharyngotympanic tube (Eustachian tube)?
Equalises the pressure on either side of the tympanic membrane by allowing a connection between the middle ear and the nasopharynx
Where are the ethmoidal cells found?
Medial to the orbit
What is the clinical relevance of the sphenoid sinus in relation to the pituitary gland?
It is penetrated in transphenoidal hypophysectomy
What significant structure is found inferior to the middle nasal concha? Which sinus drains to the bottom of this structure?
Semilunar Hiatus
Maxillary sinus
What are the three parts of the ethmoidal air cells and where do each of them drain?
Anterior, middle + posterior
Posterior: lateral wall of superior meatus
Middle: ethmoidal bulla
Anterior: top of the semilunar hiatus via the frontonasal duct with the drainage of the frontal sinus
Where does the nasolacrimal duct drain and what is its role?
To the lateral wall of the inferior meatus
It drains tears from the lacrimal sac to the nasal cavity
State 3 roles of the sinuses in the skull.
Make the skull lighter
Provide crumple zone for the brain
Increase projection of the voice
What are the mastoid air cells and describe its connection with the middle ear.
Small sinuses within the mastoid part of the temporal bone
Mastoid air cells communicate with the middle ear via the aditus ad antrum + the mastoid antrum
= a possible route for infection of the middle ear
What is the name given to the thin plate of bone that forms the roof of the tympanic cavity?
Tegmen tympani
Through which membrane is a cricothyroidotomy performed?
Cricothyroid ligament
What important cartilage is found attached to the top of the cricoid cartilage? What object is the cricoid cartilage likened to?
Arytenoid cartilage Signet ring (broad posteriorly, thinner anteriorly)
What effect does tilting the thyroid cartilage forwards have on the vocal folds? Which muscles perform this action?
Puts tension on the vocal folds
Cricothyroid muscles
What are the two parts of the cricoid cartilage?
Lamina
Arch
What two things do the cricoid cartilage articulate with?
Arytenoid cartilage
Inferior horns of the thyroid cartilage
What name is given to the protrusion between the laminae of the thyroid cartilage and what notches are found above and below this point?
Laryngeal prominence
Superior + inferior thyroid notch
What two bits of cartilage are found on top of the arytenoid cartilage?
Corniculate + Cuneiform Cartilage
What are the two folds in the mucosa in the laryngeal inlet and how are they arranged?
Vestibular Fold (false vocal fold) Vocal Fold (true vocal fold) Vestibular folds are lateral to the vocal folds
What membranous outpouching is formed between the vestibular and vocal folds?
Laryngeal ventricle and laryngeal saccule
What is the name given to the opening between the vocal folds?
Rima glottidis
Which muscles are attached only to the arytenoids?
Transverse + Oblique Arytenoid muscles
Which muscles are involved in abducting and adducting the vocal folds?
Posterior cricoarytenoid muscle: abduction
Lateral cricoarytenoid muscle: adduction
Which nerve provides sensory and motor control of the larynx?
Vagus Nerve
What are the different laryngeal branches of the vagus nerve and what do these branches do?
Superior: separates into internal + external laryngeal
Internal: sensory above vocal folds
External: motor to cricothyroid muscles
Recurrent Laryngeal: sensory below vocal folds + motor to all other muscles of the larynx
Which arteries do the superior and recurrent laryngeal nerves run alongside?
Superior: Superior thyroid artery
Recurrent: Inferior thyroid artery
Why is the left recurrent laryngeal nerve more susceptible to damage by bronchial/oesophageal tumours and swollen mediastinal lymph nodes than the right recurrent laryngeal nerve?
Left branches off the vagus much more inferiorly than the right so has more of its length that is near the bronchus, oesophagus + mediastinal lymph nodes
What are the 4 common changes that occur during sneezing and coughing?
Inspiration
Closed glottis + contraction of abdominal muscles
Increase in intrathoracic pressure
Sudden abduction of the vocal folds to release the intrathoracic pressure
What is the difference in the oropharyngeal isthmus in coughing compared to sneezing?
In coughing, the oropharyngeal isthmus is open
When sneezing, it is closed
Which afferents take information from laryngeal receptors to trigger the cough reflex?
Vagus
Which afferents take information from laryngeal receptors to trigger the sneeze reflex?
Maxillary branch of the Trigeminal nerve
How is the movement of the soft palate different in cough reflex compared to a sneeze?
Cough: soft palate is raised + tensed against the posterior wall of the pharynx
Sneeze: soft palate is depressed against the tongue
The soft palate is depressed against the tongue when sneezing to prevent the release of the pressure through the mouth. Which nerve and muscles are involved in this?
Vagus – palatoglossus/ palatopharyngeus
What happens to the vocal folds when sneezing and coughing?
They abduct
The soft palate is raised and tensed against the posterior wall of the pharynx when coughing. Which muscles are involved in this action and which nerves innervate these muscles?
Tensor veli palatini (mandibular of trigeminal (V3))
Levator veli palatini (X)
Superior constrictor (X)
What and where is the vallecula?
Behind the root of the tongue between the folds in the throat
Serve as spit traps, saliva is temporarily held in the valleculae to prevent initiation of the swallowing reflex
What is the principle function of the larynx?
Protect airways from ingested food (valve)
Phonation
Describe innervation of the upper airways
Olfactory nerve- Olfaction
Trigeminal nerve: V1 (anterior region), V2 (posterior region)
Facial nerve- glands
Sympathetic nerves (from T1): vascular smooth muscle
Describe the structure of the larynx
Hollow
Composed of cartilages, membrane + muscles
What would a lesion in the vagus nerve, internal laryngeal, external laryngeal and recurrent laryngeal cause?
Vagus: Complete paralysis
Internal: Loss of sensation above vocal folds
External: Paralysis of cricothyroid
Recurrent: Paralysis of all muscles of larynx except cricothyroid + loss of sensation below vocal folds
What procedure may be associated with damage to the superior and recurrent laryngeal nerves?
Thyroidectomy
Name 4 protective mechanisms for the airway
Swallowing
Gag reflex
Sneezing
Coughing
What does the facial nerve provide motor innervation too?
Muscles of facial expression, stapedius, digastric (posterior belly), stylohyoid
What does the facial nerve provide sensory innervation too?
Taste (ant. 2/3 of tongue)
Parasympathetic (lacrimal glands, mucous glands of nasal cavity, hard + soft palates, sublingual + submandibular glands)
General sensation from external acoustic meatus + deeper parts of auricle
What is found superior to mastoid air cells? What is the significance of this?
Middle cranial fossa
Infections can erode the bone into the cranial cavity to cause intracranial infection
