EARS AND AUDITION Flashcards
Dual Function of the ear
Maintains the balance of the body (vestibular)
Perceives sound (auditory)
3 Divisions of the ear
External ear
Middle ear
Inner ear
The most superficial portion of the ear, the ______ includes the ______, ______, and the ______
external ear, auricle, external acoustic meatus, tympanic membrane
Helps gather sound and direct it to the tympanic membrane
EXTERNAL EAR
what division of the ear?
Transmits sound vibrations from the tympanic membrane to the inner ear via the ear ossicles: ______, ______, and ______
MIDDLE EAR, malleus, incus, stapes
Mainly within the petrous portion of the temporal bone
MIDDLE EAR
General shape resembles a biconcave lens
MIDDLE EAR
Composed of the tympanic cavity that connects anteriorly with the nasopharynx via the auditory tube and the mastoid air cells posteriorly
MIDDLE EAR
what division of the ear?
______ contains the ear ossicles (malleus, incus, and stapes), muscles (tensor tympani and stapedius muscles), nerves (chorda tympani, tympanic branch of the glossopharyngeal nerve, and lesser petrosal nerve), and tympanic plexus (parasympathetics from the glossopharyngeal nerve plus sympathetics from the superior cervical ganglion via the carotid plexus)
MIDDLE EAR, Tympanic cavity
Vestibular and auditory structures, which are filled with fluid, make up the ______:
- ______ portion (cochlea) is stimulated by the movement of the fluid
- ______ portion (utricle, saccule, and semicircular canals) is stimulated by fluid
movement within these chambers
inner ear, Auditory, Vestibular
Consists of a membranous labyrinth that lies within an osseous labyrinth
INNER EAR
what division of the ear?
The receptors for auditory and vestibular function are located within the ______
INNER EAR, membranous labyrinth
what division of the ear?
Fluids located in the ______ (______) and ______ (______) stimulate the auditory and vestibular receptors
INNER EAR, membranous labyrinth, endolymph, osseous labyrinth, perilymph
what division of the ear?
The vestibulocochlear nerve enters the internal ear via the ______
INNER EAR, internal acoustic meatus
An irregularly shaped structure made of elastic cartilage and skin
AURICLE
The ______ has 2 portions: the ______ portion and the ______ portion
______ portion: has a skeleton of elastic cartilage
______ portion: is known as the lobule, and has no cartilage
auricle, superior, inferior, Superior, Inferior
AURICLE
______: the outermost curved rim of the auricle, continues anteriorly to blend with the head at the crus helix
Helix
AURICLE
______: the portion of cartilage that follows along the helix from the inside
Antihelix
AURICLE
______: the depressed area between the helix and the antihelix
Scaphoid fossa
AURICLE
______: demarcated by the antihelix, it is the
depressed area that leads to the external
acoustic meatus
Concha
AURICLE
______: extends from the face into the concha
Tragus
AURICLE
______: extends from the inferior portion of the antihelix into the concha and is separated from the tragus by the intertragic notch
Antitragus
The passageway connecting the concha of the auricle to the tympanic membrane
EXTERNAL ACOUSTIC MEATUS
Covered by skin rich in sebaceous and cerumen-secreting glands
EXTERNAL ACOUSTIC MEATUS
About 2.5 cm in length
EXTERNAL ACOUSTIC MEATUS
______ of the external acoustic meatus: cartilaginous, extends into the temporal bone
Lateral 1/3
______ of the external acoustic meatus: osseous, formed by the tympanic, squamous, and petrous
portions of the temporal bone
Medial 2/3
The most medial portion of the external ear that separates it from the middle ear
TYMPANIC MEMBRANE
Lies in a groove on the tympanic part of the temporal bone
TYMPANIC MEMBRANE
A thin, semitransparent, 3-layered membrane
TYMPANIC MEMBRANE
The tympanic membrane is A thin, semitransparent, 3-layered membrane:
- ______ layer: derived from skin; composed of stratified squamous epithelium
- ______ layer: fibrous, with fibers attaching to the malleus
- ______ layer: continuous with the mucous membrane of the middle ear cavity; composed of columnar epithelium with cilia
External, Middle, Inner
______ folds: lie on the superior portion of the tympanic membrane
Anterior and posterior malleolar
______ and ______: tense and loose portions, respectively
Pars tensa, pars flaccida
- Made by the tegmen tympani
- It separates the middle ear from the temporal lobe of middle cranial fossa
ROOF
A thin bone seprates the middle ear from the internal jugular vein
FLOOR
______, located in the floor of the middle, allows the tympanic branch of the glossopharyngeal nerve to enter the middle ear
Tympanic canaliculus
WHAT WALL?
- ______ connects the middle ear with the nasopharynx, equilibrates pressure on either side of the tympanic membrane, and allows proper drainage of the middle ear
- ______ nerve exits the middle ear
- ______ nerve fibers from the internal carotid artery enter the middle ear
ANTERIOR WALL, Auditory tube, Lesser Petrosal, Postganglionic sympathetic
WHAT WALL?
- ______ passes superoinferiorly until it terminates at the styomastoid foramen
- ______ is located in the superior portion of the posterior wall near the junction with the roof of the middle ear
- ______ is a hollow projection that contains the tendon of the stapedius muscle
- ______ and ______ are posterior to the posterior wall
POSTERIOR WALL, Facial canal, Mastoid antrum, Pyramid, Posterior cranial fossa, sigmoid sinus
WHAT WALL?
- Separates the middle and inner ear
- ______ is a large protuberance created by the cochlea of the inner ear
- In the superior portion of the medial wall is a protuberance formed by the lateral semicircular canal
- Inferior to the lateral semicircular canal on the opposite side of the medial wall is the horizontal portion of the facial canal
- ______ is an oval window where the footplate of the stapes is located
- ______ is a round window which is an opening covered by a membrane
- Both are located in a superior-inferior relationship on the medial wall posterior to the promontory
- Tendon of the ______ muscle enters the middle ear
MEDIAL WALL, Promontory, Fenestra Vestibuli, Fenestra Cochleae, tensor tympani
WHAT WALL?
- Separates the middle ear from the external ear by the tympanic membrane, with the malleus attached to the membrane at the umbo
- ______ is the region superior to the tympanic membrane that houses portions of the malleus and incus
- ______ nerve lies along the tympanic membrane and malleus until exiting the petrotympanic fissure
LATERAL WALL, Epitympanic recess, Chorda tympani
The Inner Ear is Divided in to 2 main parts the ______ Labyrinth and the ______ Labyrinth.
Osseous, Membranous
______ contains the bony parts and the ______ contains the membranes of the Inner ear.
Osseous, Membranous
Located in the petrous portion of the temporal bone Surrounds the membranous labyrinth and contains perilymph Connects to the middle ear via the fenestra vestibuli and the fenestra cochleae. Divided into 3 parts: vestibule, cochlea, and semicircular canals
The Osseous Labyrinth
Located within the osseous labyrinth; contains endolymph, Divided into 4 parts: cochlear duct, saccule, utricle, and semicircular ducts
The Membranous Labyrinth
parts of The Osseous Labyrinth
vestibule, cochlea, and semicircular canals
parts of The Membranous Labyrinth
cochlear duct, saccule, utricle, and semicircular ducts
It is The middle portion of the osseous labyrinth, it contains the saccule and utricle of the membranous labyrinth
Contains an opening for the vestibular aqueduct containing the endolymphatic duct.
VESTIBULE
The posterior portion of the osseous labyrinth 3 ______: anterior, posterior, and lateral
______: a dilated end of each
Anterior and posterior semicircularcanals have a common crus.
semicircular canals, Ampulla
The ______ of the membranous labyrinth Like a seashell, it spirals around a central point (the modiolus), which carries branches of the cochlear nerve. to it, for 2 and ¾ turns, getting progressively smaller while approaching its apex as the cochlea spirals, the spiral lamina is raised from the modiolus
Within the spiral lamina, the it lies between the scala vestibuli and the scala tympani. Scala vestibuli and scala tympani are continuous at the helicotrema at the apex an opening for the aqueduct of the cochlea allows perilymph to drain into the cerebrospinal fluid.
cochlear duct
The ______ a small structure located within the vestibule of the osseous labyrinth
Connected to the utricle via the utriculosaccular duct and the endolymphatic duct Sensory receptors (the ______) are located here
Saccule, maculae
The ______ Located within the vestibule of the osseous labyrinth Sensory receptors (maculae) are located here
Utricle
These Correspond to the semicircular
canals of the osseous labyrinth (anterior, posterior, and lateral)
Open into the utricle via 5 openings Sensory receptors known as ______ are located in the ampullae
SEMICIRCULAR DUCTS, crista
AUDITORY NERVOUS PATHWAYS
- Nerve fibers from the spiral ganglion of ______ enter the ______ and ______ cochlear nuclei located in the upper part of the medulla.
Corti, dorsal, ventral
AUDITORY NERVOUS PATHWAYS
- At this point, all the fibers synapse, and second-order neurons pass mainly to the opposite side of the brain stem to terminate in the ______ nucleus. A few second-order fibers also pass to the same nucleus on the same side.
superior olivary
AUDITORY NERVOUS PATHWAYS
- From the superior olivary nucleus, the auditory pathway passes upward through the ______.
lateral lemniscus
AUDITORY NERVOUS PATHWAYS
- Some of the fibers terminate in the nucleus of the ______, but many fibers bypass this nucleus and travel on to the ______, where all or almost all the auditory fibers synapse.
lateral lemniscus, inferior colliculus
AUDITORY NERVOUS PATHWAYS
- From there, the pathway passes to the ______ nucleus, where all the fibers do synapse.
medial geniculate
AUDITORY NERVOUS PATHWAYS
- Finally, the pathway proceeds by way of the ______ to the ______, located mainly in the superior gyrus of the temporal lobe
auditory radiation, auditory cortex
AUDITORY NERVOUS PATHWAYS
Several important points should be noted:
- Signals from both ears are transmitted through the pathways of both sides of the brain, with a preponderance of transmission in the contralateral pathway. In at least three places in the brain stem, crossing over occurs between the two pathways: (1) in the ______ body, (2) in the commissure between the two nuclei of the ______, and (3) in the commissure connecting the two ______.
trapezoid, lateral lemnisci, inferior colliculi
AUDITORY NERVOUS PATHWAYS
Several important points should be noted:
- Many collateral fibers from the auditory tracts pass directly into the ______ activating system of the brain stem. This system projects diffusely upward in the brain stem and downward into the spinal cord and activates the entire nervous system in response to loud sounds. Other collaterals go to the ______, which is also activated instantaneously in the event of a sudden noise.
reticular, vermis of the cerebellum
AUDITORY NERVOUS PATHWAYS
Several important points should be noted:
- A high degree of spatial orientation is maintained in the fiber tracts from the cochlea all the way to the cortex. In fact, there are ______ spatial patterns for termination of the different sound frequencies in the cochlear nuclei, ______ patterns in the inferior colliculi, ______ precise pattern for discrete sound frequencies in the auditory cortex, and at least ______ other less precise patterns in the auditory cortex and auditory association areas.
The projection area of auditory signals to the cerebral cortex is shown in the figure, which demonstrates that the auditory cortex lies principally on the supratemporal plane of the ______ gyrus but also extends onto the ______ of the temporal lobe, over much of the insular cortex, and even onto the lateral portion of the ______.
three, two, one, five, superior temporal, lateral side, parietal operculum
______ is directly excited by projections from the medial geniculate body.
Primary auditory cortex
______ are excited secondarily by impulses from the primary auditory cortex, as well as by some projections from thalamic association areas adjacent to the medial geniculate body.
Auditory association areas
Origin of TENSOR TYMPANI
Origin: Bony canal at auditory tube
Cartilaginous part of auditory tube
Greater wing of the sphenoid
Insertion of TENSOR TYMPANI
Insertion: Handle of the malleus
Actions of TENSOR TYMPANI
Actions: Tenses the tympanic membrane and helps dampen sound vibrations
Nerve supply of TENSOR TYMPANI
Nerve Supply: Mandibular division of the trigeminal n.
Origin of STAPEDIUS
Origin: Pyramid on posterior wall of the tympanic cavity
Insertion of STAPEDIUS
Insertion: Neck of the stapes
actions of STAPEDIUS
Actions: Dampens excessive sound vibrations
Nerve supply of STAPEDIUS
Nerve Supply: Stapedius branch of the facial n.
WHAT NERVE?
- Cervical plexus, formed by contributions of C2 and C3 ventral rami
- After passing posteriorly at the sternocleidomastoid m. it travels along the muslce and divides into anterior and posterior branches
- The posterior branch innervates the skin over the mastoid process, the posterior portion of the auricle, and the concha and lobule
GREAT AURICULAR NERVE
WHAT NERVE?
- Cervical plexus, formed by contributions from C2 ventral ramus
- After passing posterior to the sternocleidomastoid m. at Erb’s point, it ascends posterior to the sternocleidomastoid along the posterior portion of the head
- Continues on the head posterior to the auricle
- Supplies the skin posterior to the auricle
LESSER OCCIPITAL NERVE
WHAT NERVE?
- Posterior part of the mandibular division of the trigeminal n.
- Normally arises by 2 roots, between which the middle meningeal a. passes
- Runs posteriorly just inferior to the lateral pterygoid m. and continues to the medial aspect of the neck of the mandible
- Turns superiorly with the superficial temporal vessels between the auricle and condyle of the mandible deep to the parotid gland
- On exiting the parotid gland, ascends over the zygomatic arch
- Innervates the skin in the region of the tragus, crus helix, anterior portion of the external acoustic meatus, and outer surface of the tympanic membrane
AURICULOTEMPORAL NERVE
WHAT NERVE?
- Superior ganglion of the vagus n.
- Travels posterior to the internal jugular v. and passes along the temporal bone
- Crosses the facial canal superior to the stylomastoid foramen
- Enters the mastoid canaliculus between the mastoid process and the tympanic part of the temporal bone and gives rise to 2 branches:
The 1st branch joins the posterior auricular
branch of the facial n.
The 2nd branch innervates the skin of the
back of the auricle and the posterior portion
of the external acoustic meatus
AURICULAR BRANCH OF THE VAGUS NERVE
WHAT NERVE?
- Branches from the inferior ganglion of the vagus n., located in the petrous portion of the temporal bone
- Passes superiorly through the tympanic canaliculus to enter the middle ear
- In the middle ear, it divides into branches that form part of the tympanic plexus
- Tympanic plexus gives rise to:
Preganglionic parasympathetic fibers to the parotid gland
Postganglionic sympathetic fibers to the parotid gland
Sensory fibers to the middle ear cavity, including the tympanic membrane and auditory tube (mainly from the tympanic branch of the glossopharyngeal n.)
TYMPANIC BRANCH OF GLOSSOPHARYNGEAL NERVE
It is Formed by the:
- Tympanic branch of the glossopharyngeal n. (arises from the inferior ganglion located in the petrous portion of the temporal bone)
- Caroticotympanic nn. (arise from the carotid plexus
- Tympanic branch of the glossopharyngeal n. passes superiorly through the tympanic canaliculus to enter the middle ear
- In the middle ear, it divides into branches that form the tympanic plexus
- Caroticotympanic nn. join the tympanic branch of the glossopharyngeal n.
- Tympanic plexus gives rise to:
Preganglionic parasympathetic fibers to the parotid gland
Postganglionic sympathetic fibers to the parotid gland
Sensory fibers to the middle ear cavity, including the tympanic membrane and auditory tube (mainly from the tympanic branch of the glossopharyngeal)
TYMPANIC PLEXUS
WHAT NERVE?
- has multiple motor and sensory functions
- Created by:
Nervus intermedius, which contains the sensory fibers and the parasympathetic fibers
Motor portion that innervates the muscles derived from the 2nd pharyngeal archauditory tube (mainly from the tympanic branch of the glossopharyngeal) - Nervus intermedius and motor portions—enter the internal acoustic meatus of the temporal bone then passes through the facial canal until it exits the stylomastoid foramen, initially traveling horizontally along the outside of the medial wall of the middle ear; then it bends posteriorly and inferiorly to the middle ear where the nerve changes direction is in the geniculate ganglion; here the greater petrosal n. is given off to travel anteriorly toward the pterygopalatine fossa
FACIAL NERVE
WHAT NERVE?
- Within the facial canal, this nerve gives rise to the nerve to the stapedius m. and the chorda tympani n.
Chorda tympani passes anteriorly along the tympanic membrane and the malleus until it exits via the petrotympanic fissure - Chorda tympani carries preganglionic parasympathetic fibers to the submandibular ganglion of the oral cavity, and taste fibers to the anterior 2/ 3 of the tongue
- Stapedius n. innervates the stapedius m.
FACIAL NERVE
WHAT NERVE?
- it emerges between the pons and the medulla oblongata
- Enters the internal acoustic meatus with the facial n. Within the internal acoustic meatus, it divides into vestibular branches and the cochlear branch
VESTIBULOCHOCHLEAR NERVE
WHAT NERVE?
- The cochlear portion has nerve cell bodies in the spiral ganglion
- Utilizes the spiral ganglion within the modiolus to pass to the organ of Corti
COCHLEAR NERVE
WHAT NERVE?
- The vestibular portion has nerve cell bodies in the vestibular ganglion (Scarpa’s ganglion)
- Divides into superior and inferior branches:
Superior vestibular branch innervates the maculae of the saccule and utricle and the ampulla of the anterior and lateral semicircular ducts
Inferior vestibular branch innervates the macula of the saccule and the ampulla of the posterior semicircular duct
VESTIBULAR NERVE
4 Arterial Supply of the External Ear
Superficial temporal, Posterior Auricular, Deep Auricular, Anterior tympanic
WHAT ARTERY?
Source: A terminal branch of the external carotid a. that arises within the parotid gland
Course:
- Within the parotid gland, it gives off a transverse facial a.
- Emerges from the superior part of the parotid gland immediately posterior to the temporomandibular joint and anterior to the external auditory meatus
- Passes superficial to the root of the zygomatic arch just anterior to the auriculotemporal n. and the auricle.
- While passing superiorly, it gives off branches
external acoustic meatus that supply the auricle and the external acoustic meatus
Superficial temporal
WHAT ARTERY?
Source: External carotid a. within the parotid gland
Course:
- Passes superiorly between the mastoid process and cartilage of the ear
- During its path to anastomose with the superficial temporal and the occipital aa., it supplies the auricle and external acoustic meatus
- A stylomastoid branch arises from the posterior auricular and enters the stylomastoid foramen to supply the internal surface of the tympanic membrane
Posterior Auricular
WHAT ARTERY?
Source: A branch of the maxillary a. and arises in the same area as the anterior tympanic a.
Course:
- Lies in the parotid gland, posterior to the temporomandibular joint, where it supplies that joint
- Passes into the external acoustic meatus to supply it; then supplies the outer surface of the tympanic membrane
Deep Auricular
WHAT ARTERY?
Source: A branch of the maxillary a.
Course:
- Given off in the same area as for the deep auricular a.
- Passes superiorly immediately posterior to the temporomandibular joint
- Enters the tympanic cavity through the petrotympanic fissure
- Aids in supplying the inner surface of the tympanic membrane
Anterior tympanic
5 Arterial Supply of the Middle Ear
Posterior auricular, Anterior tympanic, Inferior tympanic, Superior tympanic, Caroticotympanic branch of the internal carotid
WHAT ARTERY?
Source: External carotid a. within the parotid gland
Course:
- Passes superiorly between the mastoid process cartilage of the ear
- During its path to anastomose with the superficial temporal and the occipital aa., it supplies the auricle and external acoustic meatus
- A stylomastoid branch arises from the posterior auricular a. and enters the stylomastoid foramen to supply the internal surface of the tympanic membrane
Posterior auricular
WHAT ARTERY?
Source: Maxillary a.
Course:
- Given off in the same area as for the deep auricular a.
- Passes superiorly immediately posterior to the temporomandibular joint
- Enters the tympanic cavity through the petrotympanic fissure
- Aids in supplying the outer surface of the tympanic membrane and the anterior portion of the tympanic cavity
Anterior tympanic
WHAT ARTERY?
Source: Ascending pharyngeal a. of the external carotid a.
Course:
- Ascends deep to the other branches of the external carotid a. and more superiorly to the stylopharyngeus m.
- Passes into the middle ear through the petrous portion of the temporal bone Helps supply the medial wall of the tympanic cavity
Inferior tympanic
WHAT ARTERY?
Source: Middle meningeal a. of the maxillary a.
Course:
- Arises from the middle meningeal a. immediately after passing through the foramen spinosum within the middle cranial fossa
- Passes in the canal of the tensor tympani m. to help supply the tensor tympani and its bony canal
Superior tympanic
WHAT ARTERY?
Source: Internal carotid a.
Course:
- Passes into the tympanic cavity through an aperture in the carotid canal
- Helps supply the middle ear
Caroticotympanic branch of the internal carotid
2 Arterial Supply of the Inner Ear
Labyrinthine, Posterior auricular
WHAT ARTERY?
Source: Basilar a., which gives rise to the circle of Willis
Course:
- Passes through the internal acoustic meatus, where it further divides into cochlear and vestibular branches that supply the cochlear and vestibular structures
Labyrinthine
WHAT ARTERY?
Source: External carotid a. within the parotid gland
Course:
- Stylomastoid branch supplies the internal surface of the tympanic membrane and the posterior portion of the tympanic cavity; then helps supply the inner ear
- Passes superiorly between the mastoid process and cartilage of the ear
- Anastomoses with the superficial temporal and the occipital aa.
- A stylomastoid branch arises from this a., enters the stylomastoid foramen, and continues to the inner ear
- During its path to anastomose with the superficial temporal and the occipital aa., it supplies the auricle and external acoustic meatus
Posterior auricular
5 Venous Drainage of the External Ear
Superficial temporal, Posterior auricular, Maxillary, Pterygoid plexus, Transverse sinus
WHAT VEIN?
- Descends posterior to the zygomatic root of the temporal bone alongside the auriculotemporal n. to enter the substance of the parotid gland
- Unites with the maxillary v. to form the retromandibular v.
- Along its path, it receives tributaries from the auricle
Superficial temporal
WHAT VEIN?
- Arises from a plexus of veins created by the occipital and superficial temporal.
- Descends posterior to the auricle to unite with the posterior division of the retromandibular to form the external jugular.
- Along its path, receives blood from the stylomastoid branch of the posterior auricular which drains the auricle, external acoustic meatus, and tympanic membrane
Posterior auricular
WHAT VEIN?
- A short vein, sometimes paired, formed by the convergence of the tributaries of the pterygoid plexus
- Enters the substance of the parotid gland, traveling posteriorly between the sphenomandibular and the neck of the mandible
Unites with the superficial temporal to form the
retro mandibular. - Helps drain blood from the external acoustic meatus and tympanic membrane
Maxillary
WHAT VEIN?
- An extensive network of veins that parallels the 2nd and 3rd parts of the maxillary.
- Receives branches that correspond to the same branches of the maxillary.
- Tributaries eventually converge to form a short maxillary.
- Communicates with the cavernous sinus, pharyngeal venous plexus, and facial vein via the deep facial and ophthalmic.
- Helps drain the external acoustic meatus
Pterygoid plexus
WHAT VEIN?
- 1 of the deep venous sinuses that helps drain the brain Aids in receiving blood from the tympanic membrane
Transverse sinus
2 Venous Drainage of the Middle Ear
Pterygoid plexus, Superior Petrosal Sinus
WHAT VEIN?
- An extensive network of veins that parallels the 2nd and 3rd parts of the maxillary.
- Receives branches that correspond to the same branches of the maxillary.
- Tributaries eventually converge to form a short maxillary.
- Communicates with the cavernous sinus, pharyngeal venous plexus, and facial vein via the deep facial and ophthalmic.
- Helps drain the tympanic cavity
Pterygoid plexus
WHAT VEIN?
- 1 of the deep venous sinuses that helps drain the brain, running along the superior margin of the petrous portion of the temporal bone
- Aids in receiving blood from the tympanic cavity
Superior Petrosal Sinus
1 Venous Drainage of the Inner Ear
Labyrinthine
WHAT VEIN?
- Begins in the cochlear and vestibular structures and passes medially through the internal acoustic meatus alongside the labyrinthine.
- Drains into the superior petrosal sinus
Labyrinthine
______ - infection or inflammation of the auricle and external auditory canal located in the external ear, causing ear pain (______)
• Also called “swimmer’s ear”
• 2 major bacteria are involved:
______ and ______
Acute otitis externa, otalgia, Staphylococcus aureus, Pseudomonas aeruginosa
PATHOGENESIS of Acute otitis externa
- Excess water from swimming removes some of the ______ wax that lines the external auditory canal
• Because the wax helps maintain healthy canal, loss of the wax predisposes the canal to bacterial infection
ceruminous
______ - an inflammation of the middle ear cavity
• More common in children
• 2 major bacteria are involved: ______ and ______
Acute otitis media, Streptococcus pneumoniae, Haemophilus influenzae
PATHOGENESIS of Acute otitis media
• Often results from ______ dysfunction
• Because the auditory tube allows drainage from the tympanic cavity into the nasopharynx, any blockage leads to a buildup of fluid in the tympanic cavity
• When the fluid sits in the tympanic cavity, it predisposes the region to a bacterial infection
• The resulting inflammation leads to ear pain (otalgia) and often diminished hearing
auditory tube
______ - a bacterial infection of the mastoid air cells
• More common in children than in adults
Mastoiditis
PATHOGENESIS of Mastoiditis
• Although less common since the advent of antibiotics, formerly it often occurred as a complication of acute otitis media, when infection spread from the middle ear cavity to the mastoid air cells
• Once within the mastoid air cells, the infection can lead to inflammation and destruction of the ______ bone
• Because of the infections location , it may lead to partial (or total) hearing loss, damage to the mastoid bone, or formation of an epidural abscess, or it may spread to involve the brain
mastoid
TREATMENT of Mastoiditis
• Can be difficult because medications cannot readily reach the mastoid air cells
• In some cases, a ______ may be performed to drain the mastoid if antibiotic therapy is not successful
• A ______ (creating an opening in the middle ear cavity through the tympanic membrane) is performed to drain the ear in acute otitis media
mastoidectomy, myringotomy
______ - Prevalent among individuals who surf or swim in cold water, results from the development of a “bony lump” in the external acoustic meatus.
• Growth of the lump eventually constricts the meatus and reduces hearing in the affected ear.
Surfer’s ear
