Ear Flashcards by Charlotte Smith

What does the external ear do

Collects and conveys sound waves to tympanic mem

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What is the middle ear and what does it do

Tympanic mem to oval window
Eustanchion tube

Amplifies and conducts sound waves to internal ear

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What is the internal ear and what does it do

Oval window to internal acoustic meatus

Converts special sensory information

-> sound waves to fluid waves
-> then action potentials
-> conduct action potentials to Brian

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What kind of cartilage is the external ear

Elastic

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What does the a vascular property mean to the external ear

Take nutirents form skin

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Why do you not use adrenaline anaesthetic on ear

Adrenaline causes vasoconstriction causing necrosis of the avasvilar tissue as this tissue requires nutirents form skin and its blood supply

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Describe the ER canal

Eam
1/3 rd cart 2/3rds bony
Lined skin v thin
Produce earwax cerumin via ceruminous gland

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Give three features of the external auricle

Helix
Tragus
Lobe

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What is the general sensory innervation of the external ear

Superior parts eam and tympanic mem - CN V3 mandibular nerve

Inferior parts eam and tympanic mem - vagus nerve

Lower part of helix almost lobe - C2,3 spinal nerve

Inside part of helix - facial nerve

Top of helix - C2,3 spinal nerve

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Explain the lymphatic drainage of the ear

Lateral surface of superior half - parotid lymph nodes

Cranial surface of superior half - mastoid lymph nodes and deep cervical

Rest of auricle including lobe - superficial cervical lymph nodes

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Where does the lymphatic drainage eventually drain to

Deep cervical lymph nodes in carotid sheath
Thoracic duct or right lymphatic duct
Venous angle

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What is an otoscopic examination

Examination of the eam and tympanic mem

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How do you carry out an otoscopic examination of a child

Eam is short and straight
Do not damage tymp meme so be v careful
Gently pull auricle posteroinferiorly

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How do you carry out an otoscopic examination of an adult

Eam is curved
Gently straiten eam
Gently pull auricle posterosuoeriorly

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What is the pars flaccida

Thin part of tymp mem superiorly

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What so the pars tense

Thick part of the tympanic mem posteroinferiorly

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What is the umbo

Most inwardly depressed part of tymp mem

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Where is the cone of light

NormLly directed anteriorinferiorly

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What is the sensory innervation of the tymp mem

External - mostly V3 auriculotemporal branch

Internal - CN IX

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Where does the Glossopharyngeal nerve IX supply sensory innervation to in the ear

Middle ear cav 
Eustanchion tube
Nasopharynx
Oropharynx
Tonsils

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What does the Eustachian tube connect

Connects the tymp cav to lateral wall of nasopharynx

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What are the auditory ossicles

3 bones of Middle ear cav articulate via synovial joints

Name the Auditory ossicles

Malleus
Incus
Stapes

What is the epitympanic recess

Sup to tymp mem

What is the base of the stapes

Fits into oval window way into internal ear

What creates the umbo

The handle of the malleus adherent to internal aspect of the tymp mem

What is the aditus

Doorway to the mastoid process

What is the right promontory

Bony swelling on medial wall formed by the cochlea of internal ear

What is mastoiditis

Air cells in mastoid become infected due to spread of infection

Explain what the facial nerve does and it's course

Special sensory taste General sensory Motor Parasymp Connection to CNS - brain stem at junction between pins and medulla PONTOMEDULLARY JUNCTION inter cranial corse - direct into iam in posterior cranial fossa Base of skull foramen - iam and the stylomastoid foramen

What is the chords tympani

Branch of the facial nerve Supplies taste on anterior 2/3rd of tongue Parasymp to submand and subling salivary glands

What is significant about the right stapedius

Tiniest skeletal muscle in body suppli by facial nerve | Reduces stape movement to protect internal ear from excessive noise

What does the tensor tympani do

dampens noise of chewing supplied by facial nerve

What is the facial nerve extra cranial course

Exit cranial cav via internal acoustic meatus Facial nerve through stylomastoid foramen Chordae tympani branch connects to lingual nerve branch of V3 to supply parasymp secretomotor to submandibular and sublingual glands Facial nerve supply muscles of facial expression

What are some muscle of facial expression

Frontalis Orbicularis oculi- oris Elevators of lip

What do facial expression muscles do and originate from

Originate - on bone and insert into superficial fascia | Pull on skin when contracted

How can u clinically test facial expression and motor function of facial nerve

``` Ask pt to Frown Close eyes tight Smile Puff out cheeks ```

What is the buccal fat pad

On Buccinator | Loss in illness - sunken cheeks clinical sign of malnutrition

What is the vermillion border

Border between skin and fascia of lips transition zone

What are the two parts of the vestibulocochlear nerve

Cochlear nerve - hearing | Vestibular nerve - balance

What does the otic capsule contain

Bony labyrinth

What does the bony labyrinth filled with

Fluid peri lymph filled | Spaces inside otic capsule

What is suspended within the perilymph of the bony labyrinth

Membranous labyrinth Communicating sacs and ducts Contains endolymph fluid

Where does the dense otic capsule sit

Temporal bone

What su the perilymph

Fluid that fills the bony labyrinth | The ,ends nous labyrinth floats in bony labyrinth

What are the two windows of the bony labyrinth

Oval and round

What is the cochlear duct and what does it do

A long balloon like strict within the cochlea filled with endolymph Action pots conducted to brain stem in cochlear nerve

What are the semi circular ducts

Inter linked balloon like structures within semicircular canals filled with endolymph Action potentials conducted to brain stem in vestibular nerve

What is the sequence of sound transmission

1- sound waves make tymp mem vibrate 2- vibrations transmit through ossicles 3- base of stapes vibrates in oval window 4- vibration of stapes creates pressure waves in perilymph 5- hair cells in cochlea are moved neurotransmitter is released, action potentials stimulated and conveyed to brain by cochlear nerve 6- pressure waves descend and become vibrations again 7- pressure waves dampened at the round window

What is the course of the vestibulocochlear nerve

CN 7 and CN 8 connect with brains team at the junctions between pons and medulla oblongata Vestibulocochlear nerve at internal acoustic meatus Cochlear axon nerves Vestibular nerve axons form semicircular ducts

What are some symptoms of pathology of CN vii in internal acoustic meatus

Ipsilateral- loss facial expression, loss of taste Dry mouth Reduced sensation in auricle

What are the symptoms of associated pathology internal acoustic meatus of CN viii

Ipsilateral- loss of hearing, loss of balance

What does the external part of the ear compose of

Auricular piña to tympanic mem drum | Lead to eam