Nasal cavity, paranasal sinuses and pharynx and its clinical anatomy Flashcards
role of nose
olfaction - smell respiration filtration of dust humidification and warmth reception and elimination of secretions
external nose
mostly cartilage nares - nostrils bounded by alae skin extends into vestibule has hairs for filtration
bones of the external nose
nasal
maxillary
frontal
septum
cartilage of external nose
5 main parts
what makes up the septum?
ethmoid bone
vomer bone
cartilage
maxilla and palatine bones nasal crests
walls of nose
floor, roof, medial and lateral walls
Nasal cavity
divided by septum, entry through nares, exit to nasopharynx (choanae)
Lined by mucosa
except vestibule
continuous with pharynx and paranasal sinuses, lacrimal sac and conjunctiva
olfactory area - superior 1/3
role of conchae/ turbinates
increased surface area for heat exchange
nasal 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
can be hyperaerated
vasculature of nasal cavity
5 sources superior 3 have septal and lateral branches Kiesselbach area external nose submucosal venous plexus
venous drainage of the external nose
opthalmic veins
cavernous sinus
pterygoid plexus
facial vein
nerve supply of external nose
maxillary and opthalmic branches
most of external nose by V1
olfactory nerve
sphenoid sinus
only thin bone separating from optic nerves and chiasm. Pituitary gland, internal carotid arteries and cavernous sinus
trans-sphenoidal 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
ethmoidal 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 .
otorrhoea
discharge from the ear from ear canal or middle ear
nasal and facial fractures
common
causing septal deviation
rhinitis
Urticaria and allergy
sinusitis
infection can spread intracranially
nasopharynx to middle ear
eustachian tube
Pharynx
part of upper aerodigestive tract
cranial base to oesphagus
there are 3 parts
what are the 3 parts of the pharynx?
nasopharynx
oropharynx
laryngopharynx
nasopharynx
respiratory function
from nasal choanae to soft palate
eustachian tube orifice
oropharynx
digestive function
soft palate to base of tongue
laryngopharynx
epiglottis to oesophagus
Pharyngeal muscle
longitudinal muscle internal to circular layer
opposite to rest of alimentary tract
external circular layer
pharyngeal constrictors superior middle inferior inferior has sphincteric function involuntary sequential contraction to propel food bolus
nerve supply of external circular layer of pharynx
pharyngeal nerve plexus from vagus, glossopharyngeal and sympathetic cervical ganglia
gaps between the muscles allows passage of nerves and arteries
internal longitudinal layer of pharynx
palatopharyngeus
stylopharyngeus
salpingopharyngeus
they elevate the larynx and shorten and widen the pharynx during swallowing and speaking
swallowing
deglutition
3 phases
what are the phases of swallowing
- voluntary chewing and pushing into oropharynx
- involuntary soft palate seals off nasopharynx, larynx elevates, widens pharynx
- involuntary - sequential contraction of pharyngeal constrictors causes peristalsis into oesophagus
tonsilar ring
pharyngeal tonsils -
tubal tonsil
palatine tonsils -
tonsils
aggregated lymphoid tissue
Pharyngeal tonsils
adenoid on roof and posterior wall of nasopharynx
Tubal tonsils
- near eustachian tube orifice
palatine tonsils
each side of oropharynx between palatine arches
lingual tonsils
posterior part of tongue
vessels
tonsilar branch of facial artery and others
ascending and descending palatine, lingual, ascending pharyngeal
large paratonsilar vein to pharyngeal venous plexus
highly vascular can bleed a lot during or after surgery
lymphatic drainage of tonsils
tonsilar lymphatic vessels to juugulodigastric cervical lymph node
Nervous supply of tonsils
pharyngeal plexus vagus - motor glossopharyngeal - sensory some nasopharyngeal sensation from maxillary branch of trigeminal nerve gag reflex
what muscles of the pharynx are innervated by the vagus nerve
all muscles of pharynx and soft palate except stylopharyngeus and tensor velipalatini
some motor to inferior constrictor from external and recurrent laryngeal branches
Eustachian tube
more horizontal in children
can be associated with middle ear infections
more difficult to equalise so painful during air travel
ear cancer
nasopharyngeal mass/ cancer in adults can lead to middle ear obstruction
foreign body
usually in piriform fossa
lateral to laryngeal opening
can damage internal and recurrent laryngeal nerves deep to here
pharyngeal pouch
zenker diverticulum outpouching of hypopharynx just superior to upper oesophageal spchincter between 2 parts of inferior constrictor killian dehiscence pulsion pseudo diverticulum
what can happen in the pharyngeal pouch?
trapped food and liquid dysphagia halitosis regurgitation cough aspiration infection
orbital plate of ethmoid bone
fractures easily due to thin bone
infection
can spread from ethmoid fracture upwards but CSF moves down
epiglottis
start of larynx
