ENT Flashcards
Modality of CN1
Special sensory
Outline CN1
Shortest cranial nerve
Does not join with brain stem
Unmyelinated
Consists of two processes - peripheral olfactory processes in mucosa
And antral processes that return info to the brain
Enters through cribriform plate of ethmoid bone
What is in the olfactory bulb
Specialised mitral cells that synapse with olfactory nerve
Does olfactory nerve go to the thalamus
Nope
What lines the sinuses
Mucous secreting respiratory mucosa
Where does the right ethmoidal sinus drain to
Right superior and middle meatuses
Where does sphenoidal sinuses drain to
Anteriorly into the right sphenoethmoidal recess
Frontal sinuses drain to,,,
Right Middle meatus
Antra drain to
middle meatus
Where do tears drain to ?
Nasolacrimal duct
Which drains tears into the inferior meatus of lateral wall of nasal cavity
What is sinusitis
Inflammation of the mucosa of the para nasal sinuses
Acute subacute or chronic
Infective - usually viral, allergic or autoimmune
Where is the pain of sinusitis felt
In the distribution of cnV1 and CNV2 and may be referred to the teeth
Why are the antral/maxillary sinuses most liable to sinusitis
Because the mucous here has to drain up against gravity
What does the Petrous part of the temporal bone contain
Organs of hearing and balance
Facial nerve
Vestibulocochlear nerve
What does the external acoustic meatus do
Collects and conveys sound waves to the tympanic membrane
What does the Eustachian tube do
Regulates pressure
Aerates the middle ear system
Why must you not use adrenaline containing local anaesthetics on the ear
As the cartilage is avascular
Where do the mastoid nodes Drain to
Post auricular
Then to deep cervical then to thoracic duct
Where do the parotid nodes drain
Pre auricular then deep cervical then thoracic duct
What are the four parts of the tympanic membrane
Umbo is the most inward bit
Pars flaccida is the thinnest bit
Pars tensa is the thick part
Cone of light
What is the general sensory nerve supply to the tympanic membrane
External - CNV3
Internal - CN IX
What is the general sensory nerve supply to the middle ear, Eustachian tube, nasopharynx, oropharynx and tonsils
CN IX
Where does the Eustachian tube connect
Connects the tympanic membrane to lateral wall of nasopharynx
What is the aditus
The doorway into the right mastoid Antrum (the air cells in the ,a stood process)
What is the bony labyrinth
The space inside the otic capsule
What is perilymph
The fluid that fills the bony labyrinth
What are the semicircular ducts
Inter linked balloon like structures within the semi circular canals containing endolymph
APs here -> vestibular nerve
What is stapedius
Tiniest skeletal muscle in the body
Supplied by CN VII
reduces stapes movement to protect from excess noise
What is tensor tympani
Tiny skeletal muscle
Supplied by CNV3
Pulls on handle of malleus to tense the tympanic membrane
What is chorda tympani
Branch of CN VII
Supplies taste buds to anterior 2/3 tongue
Parasympathetic supply to submandibular and sublingual glands
Where does CN VII exist for its extra cranial course
Stylomastoid foramen
It enters the posterior aspect of parotid gland and divides into somatic motor branches for facial expression
What supplies the salivary glands
Parotid - parasym from CN IX
Submandibular and sublingual - parasym from chorda tympani
What is the parotid duct
Crosses the masseter
Pierces medically through buccinator and opens on the parotid papilla of buccal mucosa
What is the muscle of the floor of the mouth
Miylohyoid
What is the lingual nerve
Branch of CN V3 containing general sensory and special sensory from the anterior two thirds of the tongue
What is the general and special sensory supply to the posterior third of the tongue
CN IX
What is the foramen caecum
Origin of thyroid gland at apex of terminal groove
What are the extrinsic muscles of the tongue
Palatoglossis - from soft palate to tongue
Styloglossus - from styloid process of temp bone to tongue
Hyoglossus - from hyoid bone to tongue
Genioglossus - from mandible to tongue
Most supplied by CNxii which connects to CNS at medulla oblongata
What epithelium is in the oral cavity
Hard palate - keratinised stratified squamous epithelium
Soft palate - non keratinised stratified squamous epithelium
What can be done for a septal haematoma
Incised and drained to prevent avascular necrosis of the septal hyaline cartilages
