Upper airway Flashcards
3 parts of pharynx
Nasopharynx
Oropharynx
Laryngopharynx
How are airways held open
Larynx, trachea and bronchi by cartilage
Nasal cavities and pharynx by attachments to bone
Function of larynx
To protect airways during ingestion of food
Also phonation and speech
Function of nasal cavities
Warming and moistening air to protect airways of shock
Olfactory
Bones in nasal cavity
Conchae
3- superior, middle, inferior
Space in-between- meatuses
Innervation of nasal cavity
Olfactory nerve
Trigeminal nerve- V1 anterior, V2 posterior
Facial nerve- glands
Sympathetic nerves from T1- vascular SM
Blood supply of nasal cavity
Branches of external and internal carotid
Link between nasal and cranial cavity
Blood can drain from nasal cavity to cranial, which can lead to infection
Paranasal Air sinuses, function and innervation
Frontal - superior
Sphenoidal- middle posterior
Ethmoidal- middle anterior
Maxillary- inferior
Reduce weight of facial bones
Crumple zone- protects brain
Resonates voice
All supplied by trigeminal- sensory
Sinus drainage
Sphenoid drains into the nasal cavity via the spehno-ethmoidal recess
Ethmoidal air cells drain into the ethmoidal bulla between the middle and inferior concha
Frontal air sinuses and anterior ethmoidal cells drain into the nasal cavity via the frontonasal duct
Larynx position and support
Superior and posterior to thyroid gland
Supported from roof of the mouth by hyoid bone
Cartilage controlling passage of larynx
Arytenoid cartilage- attached to vocal cords
Acts as sphincter
Open during inspiration and closed in phonation
Cartilage inferior to thyroid
Cricoid- full ring
Hole between vocal cords
Rima glottidis
Muscles of larynx
Cricothyroid muscle- tensor of vocal cords
Thyroarytenoid muscle: relaxer of the vocal folds
Nerve supply of larynx
Vagus- branches -superior and recurrent laryngeal
Motor- Recurrent everything except cricothyroid muscles get from external laryngeal
Sensory - Recurrent above vocal cords
Internal- Below
Looping of left recurrent laryngeal
Loops around junction between aortic arch and pulmonary trunk
Occurs around vestigial ligament- where previous pathway was
LRL is longer
Looping of right recurrent laryngeal
Loops around right subclavian artery
Effect of larynx from lesions of vagus
Lesion before branching- complete paralysis on one side
Internal branch of Superior- loss of sensation of vocal cords- critical for reflex coughing
RRL- paralysis of almost all, loss of sensation below
Recurrent laryngeal nerve travels with the inferior thyroid artery
So the RLN is vulnerable during thyroid surgery
Sections of the ear
Outer- auricle and external auditory meatus
Middle- Ear drum, ossicles (maleus, incus and stapes)
Inner- Cochlear, vestibule and three semi-circular canals
Facial nerve pathway
Travels from pons through the facial canal in the temporal bone via stylomastoid foramen- which is in internal acoustic meatus
Motor function of facial nerve
Muscles of facial expression, stapedius, digastric (posterior belly), stylohyoid
Sensory function of facial
Taste (anterior 2/3 tongue), parasympathetic (lacrimal glands, mucous glands of nasal cavity, hard and soft palates, sublingual and submandibular glands)
General sensation from external acoustic meatus and deeper parts of auricle
Mastoid process and the eustachian tube
Mastoid air cells give honeycomb appearance
Eustachian tube is next to this and connects nasal cavity to middle ear
External ear
Auricle and external auditory meatus, which collect sound and direct it towards the tympanic membrane
Middle ear
The middle ear is an irregular air space within the temporal bone
Anteriorly, it communicates with the naso-pharynx via the pharyngo-tympanic (Eustachian) tube
The tympanic cavity is traversed by the chain of ossicles (maleus, incus and stapes)
Inner ear
The internal ear lies in the petrous temporal bone medial to the middle ear
It comprises the cochlea, vestibule and three semi-circular canals
