Nasal Cavity, paranasal sinuses and pharynx

Cards (42)

  • PHARYNX
    • Muscular tube adjoining the oral and nasal cavity to the larynx and oesophagus
    • Ends at inferior border of cricoid cartilage
    • 3 subdivisions:
    • Nasopharynx
    • Oropharynx
    • Laryngopharynx
  • NASOPHARYNX
    • Continuous with the nasal cavity
    • Respiratory function
    • Lined with respiratory epithelium
    • Posterosuperior nasopharynx contains the adenoid tonsils
  • OROPHARYNX
    Between the soft palate and the superior border of epiglottis
    Structures:
    Posterior third of tongue
    Lingual tonsils
    Palatine tonsils
    Superior constrictor muscle
    Waldeyer’s ring
    Involved in swallowing
  • LARYNGOPHARYNX
    • Between superior border of epiglottis and inferior border of cricoid cartilage
    • Continuous with the oesophagus
    • Communicates with the larynx via the laryngeal inlet
    • Contains the middle and inferior pharyngeal constrictors
  • What are the three divisions of the pharynx?
    Nasopharynx, oropharynx, laryngopharynx.
  • Where is the nasopharynx?

    Upper part of the throat, behind the nose. Nasal choanae to soft palate.
  • What is the function of the nasopharynx?

    Respiratory - conditions inspired air and propagates into larynx
  • Which cell type lines the nasopharynx?
    Pseudostratified columnar epithelium and goblet cells.
  • Where is the oropharynx?
    Back of the throat. From soft palate to superior border of epiglottis.
  • What are the contents of the oropharynx?
    Posterior third of the tongue, lingual and palatine tonsils and superior constrictor muscles.
  • What is the function of the oropharynx?
    Voluntary and involuntary swallowing, allows food to be safely delivered to the oesophagus.
  • Waldeyer's ring
    paired palatine tonsils, adenoid tonsils and lingual tonsil
  • Nose
    • olfaction (smell)
    • respiration
    • filtration of dust
    • humidification and warmth
    • reception and elimination of secretions (from paranasal sinuses and lacrimal ducts)
  • External nose has 5 cartilages
    • septal, lateral nasal major and minor, alar, and vomeronasal
    Nares (nostrils) are bound by alae.
    Skin extends into vestibule and has hairs for filtration.
  • External nose bones:
    • Nasal
    • Maxillary
    • Frontal
    • Septum
  • Nasal septum
    • Ethmoid
    • Vomer
    • Cartilage
    • Maxilla and palatine bones nasal crests
  • Nasal cavity
    • divided by septum
    • entry - nares
    • exit to nasopharynx - choanae
    • lined by mucosa
    • pseudostratified ciliated columnar cells with goblet cells
    • except vestibule
    • continuous with pharynx and paranasal sinuses, lacrimal sac and conjunctiva
    • olfactory area - superior 1/3
  • Conchae/turbinate
    • increased surface area for heat exchange
  • meatus
    • recess underneath conchae
    • common nasal meatus - nasal passageway
    • mucosa can swell blocking passages
  • Paranasal sinuses
    • air filled extensions of nasal cavity
    • named by the bones which they occupy
    • Maxillary and sphenoidal small at birth, others develop later (about 8 years old)
    • can be hyperaerated
  • Paranasal sinuses
  • Paranasal sinuses
    • frontal
    • maxillary
    • ethmoid
    • sphenoid
  • Drainage of sinuses
    • sphenoethmoidal recess
    • sphenoid sinus
    • superior meatus
    • posterior ethmoidal
    • middle meatus
    • anteriorly is the ethmoidal infundibulum
    • drains frontal sinus and anterior ethmoid
    • semilunar hiatus and ethmoid bullae
    • drains maxillary sinus
    • drains middle ethmoid sinus
    • inferior meatus
    • nasolacrimal duct
  • Arterial supply
    • kiesselbach's area (little's area)
    • anastomotic plexus on septum
    • external nose
    • from anterior ethmoid and septal and infraorbital and facial
    • submucosal venous plexus
    • thermoregulation
  • Venous drainage external nose
    • cavernous sinus
    • ophthalmic veins
    • pterygoid plexus
    • facial vein
  • Nerve supply
    • maxillary and opthalmic branches
    • most of external nose by ophthalmic
    • olfactory nerve
  • Sphenoid sinus
    • only thin bone separating from
    • optic nerves and chiasm
    • pituitary gland
    • internal carotid arteries
    • cavernous sinus
    • transsphenoidal surgery
  • Maxillary sinus
    • forms wall of nasal cavity and floor of orbit
    • posterior molar teeth can project into
    • drains via maxillary ostium into semilunar hiatus of middle meatus
    • most commonly infected (uphill drainage)
  • Ethmoid sinus
    • direct passage to anterior cranial fossa through cribriform plate
    • infection can spread from ethmoiditis
    • fracture of cribriform plate can lead to CSF rhinorrhoea
    • similar to otorrhoea
    • can test glucose content - highly unreliable
    • beta-2 transferrin
    • single best test - high sensitivity and specificity
    • no localising information though - use imaging
  • Nasal and facial fractures can lead to septal deviation.
  • Rhinitis
    • upper respiratory tract infections and allergy
    • sinusitis
  • Infection spreading
    • intracranially
    • cribriform plate
    • retropharyngeal
    • middle ear
    • pharyngotympanic (eustachian) tube
    • lacrimal apparatus and conjunctiva
    • orbital
    • thin ethmoidal walls
    • teeth to sinus or sinus to teeth
    • maxillary sinus and molar teeth
    • same nerve supply - superior alveolar nerves
  • Pharyngeal muscles
    • longitudinal muscles internal to circular layer (opposite to rest of GI tract)
  • Internal longitudinal layer Pharyngeal muscles
    • palatopharyngeus
    • stylopharyngeus
    • salpingopharyngeus
    • elevate larynx and shorten and widen pharynx during swallowing and speaking
  • External circular layer pharyngeal muscles
    • pharyngeal constrictors
    • superior, middle and inferior
    • inferior has sphincteric function
    • involuntary sequential contraction to propel food bolus
    • pharyngeal nerve plexus from vagus, glossopharyngeal and sympathetic cervical ganglia
    • gaps between allow passage of nerves and arteries etc.
  • Swallowing - 3 phases
    1. voluntary chewing and pushing into oropharynx
    2. involuntary - soft palate seals off nasopharynx, larynx elevates, widens pharynx
    3. involuntary - sequential contraction of pharyngeal constrictors causes peristalsis into oesophagus
  • Tonsillar (Waldeyer's) ring (aggregated lymphoid tissue)
    • pharyngeal tonsils (adenoids)
    • roof and post wall nasopharynx
    • tubal tonsil
    • near eustachian tube orifice
    • palatine tonsils
    • each side of oropharynx, between palatine arches
    • lingual
    • posterior part of tongue
  • Pharyngeal plexus
    • vagus - motor
    • all muscles of pharynx and soft palate except stylopharyngeus (IX) and tensor veli (V3)
    • some motor to inferior constrictor also from external and recurrent laryngeal branches
    • glossopharyngeal - sensory
    • some nasopharyngeal sensation from V2 also
    • Gag reflex
  • Arterial supply and venous drainage of pharynx
    • tonsillar branch of facial artery as well as multiple other arterial branches
    • ascending and descending palatine, lingual, ascending pharyngeal
    • large paratonsilar vein to pharyngeal venous plexus
    • highly vascular, can bleed a lot at or after surgery
    • tonsilar lymphatic vessels to jugulodigastric cervical lymph node
  • The fauces, isthmus of fauces or the oropharyngeal isthmus, is the opening at the back of the mouth into the throat. It is a narrow passage between the velum and the base of the tongue.