Head Clinical Supplement Flashcards
What is involved in an anterior fossa fracture?
Involves the cribriform plate or frontal bone
Cribiform plate: epistaxis, leakage of CSF (rhinorrhea), anosmia
Frontal bone: exophthalmos
What is involved in a middle fossa fracture?
Temporal bone – may damage CN VII and VIII; leakage of CSF from the external meatus
Involving cavernous sinus – CN III, IV, VI
What is involved in a posterior fossa?
Involvement of the jugular foramen may affect CN IX, X and XI
What is a battle sign involving posterior fossa?
Bruising over the mastoid process that occurs ~2 days after a fracture in the posterior cranial fossa
What is most commonly involved in a facial fracture?
Nasal, zygomatic arch, maxilla, orbital fractures, mandible, temporal bone, mastoid process
What is a blowout fracture of the orbit?
Result in bleeding into maxillary sinus; may entrap inferior rectus (restricted upward gaze) or inferior oblique muscle and/or lacerate the infraorbital n. (sensory loss on lower eyelid & maxilla)
What will a medial orbital fracture impact?
Impact the ethmoid»_space; sphenoid sinus; can entrap the
medial rectus muscle (restricted lateral gaze)
What does the neck of mandible fracture endanger?
Facial and auriculotemporal ns.
What does the superior ramus endanger?
Inferior alveolar and lingual ns.
What are the signs/symptoms of temporal bone fracture?
Battle sign, facial paralysis, sensorineuronal hearing loss (disruption of ossicular chain), dizziness, leakage of CSF from the external auditory meatus, hemorrhage (epidural or subarachnoid)
What will a mastoid process fracture endanger?
Facial nerve as it exits stylomastoid foramen
What is Eagle Syndrome?
- results from elongation of the styloid process or calcification of the stylohyoid ligament
- can compress cranial nerves V, VII, IX and X
- can compress the carotid artery, resulting in:
▪ visual difficulties, syncope, carotid dissection
▪ pain (eye, referred) due to irritation of the sympathetic plexus
What is the arterial support of anterior cranial fossa?
Anterior meningeal artery from anterior + posterior ethmoidal arteries
What is the arterial support of middle cranial fossa?
Middle meningeal artery + accessory meningeal artery from maxillary artery
What is the arterial support of posterior cranial fossa?
Posterior meningeal artery from ascending pharyngeal artery, branches from the vertebral, occipital and ascending pharyngeal arteries
What is the innervation of the anterior fossa?
CN V1 (from anterior + posterior ethmoidal nerves)
What is the innervation of the middle fossa?
CN V2 and CN V3
What is the innervation of the posterior fossa?
C1-3 + CN X (meningeal irritation here can cause NAUSEA)
What is the innervation of the falx cerebri?
CN V1
What is the innervation of the tentorium cerebelli?
CN V1
Where can the facial artery be palpated?
As it crosses the inferior border of the mandible, anterior to the masseter
Where can the superficial temporal artery be palpated?
Where it crosses the zygomatic arch, anterior to the ear
Why do scalp lacerations bleed profusely?
The dense connective tissue tends to hold cut vessels open
(they would otherwise collapse) and there are abundant anastomoses between the arteries supplying the scalp, especially the superficial temporal artery (across the midline) and branches from the occipital artery
Deep scalp lacerations tend to…
Gape - the epicranial aponeurosis (when cut, especially in the coronal plane) tends to retract and hold wounds open
Infections within the deep, loose connective tissue can spread
Into the cranial cavity via emissary veins -> causes meningitis
What is the Danger Triangle? Why is it named so?
a. a triangular area extending from the corners of the mouth to bridge of the nose
b. the veins draining the skin in this region (facial and ophthalamic v.) have connections to the cavernous
sinus
c. skin infections in this region can spread through venous channels:
- intracranially to the cavernous sinus (see #43)
- to the infratemporal fossa and the pterygoid venous plexus
What does the parotid duct pierce?
Buccinator muscle, enters oral cavity opposite the 2nd maxillary molars -> can be blocked by crystallized secretions
What CN transverses this gland and is in danger during a parotidectomy?
CN VII
What is the parasympathetic innervation of parotid?
By CN IX (otic ganglion) with postganglionic axons “hitchhiking” along the auriculotemporal nerve
What is the sympathetic innervation of parotid?
Superior cervical ganglion (T1-T4) via branches from external carotid nerve
What is the sensory innervation of the parotid capsule?
CN V (refers pain to ear/TMJ)
What is Frey’s syndrome?
Gustatory sweating -> may occur following surgical removal of the parotid gland or trauma (injury to auriculotemporal nerve); injured/cut parasympathetic axons grow out to innervate sweat glands on the face; seeing/smelling food = sweating on the face
What joint is the temporomandibular joint?
Combination plane/hinge joint with fibrocartilaginous disc (meniscus)
What muscles depress the mouth?
Anterior digastric, mylohyoid, inferior head of lateral pterygoid
What muscles elevate the mouth?
Masseter, temporalis, medial pterygoid, lateral pterygoid
Dislocation of mandible
Most often occur anteriorly (during depression) – the head of the mandible slides anteriorly over the articular tubercle; mandible remains depressed and cannot be elevated/closed
What is the sensory innervation of mandible?
Auriculotemporal nerve
What is the sign/symptom of mandible dislocation?
Jaw/ear pain»_space; headache > neck shoulder pain (worsened with chewing), locking of jaw, ear clicking or popping (displacement of disc)
What is the patient presentation of mandibular dislocation?
Restricted jaw opening (spasm of masseter, medial pterygoid), clicking/popping, tenderness, crepitus, lateral deviation of mandible
What does normal mean for extraocular muscles?
EOMI = extraocular muscles are intact
What does abduction test?
Lateral rectus (CN VI)
What does adduction test?
Medial rectus (CN III)
Adduction + depression tests…
Superior oblique (CN IV)
Adduction + elevation tests…
Inferior oblique (CN III)
Abduction + depression tests…
Inferior rectus (CN III)
Abduction + elevation tests…
Superior rectus (CN III)
From primary gaze, elevation tests…
Superior rectus and inferior oblique
From primary gaze, depression tests…
Inferior rectus and superior oblique
What is the accommodation? What is it controlled by?
a. changes that occur for near vision; all controlled by CN III:
- bilateral contraction of the medial rectus (GSE)
- constriction of the pupil (GVE)
- contraction of ciliary muscle (GVE) and subsequent thickening of the lens (= more refractive power)
What does PERRLA stand for?
Pupils are equal, round and reactive to light and accommodation
What is anisocoria?
Left-right asymmetry in the size of the pupils
What do 10-20% of patients have?
Benign anisocoria
What occurs in a CN III injury?
- severe ptosis (levator palpebrae), mydriasis (dilated pupil = unopposed action of dilator pupillae)
and diplopia (unopposed action of LR and SO = eye “down and out”) - more pupil asymmetry in LIGHT
What occurs in Horner’s Syndrome?
Sympathetic injury
- mild ptosis (paralysis of superior tarsal muscle), miosis in affected eye (constricted pupil =
unopposed action of constrictor pupillae)
- more pupil asymmetry in DARK
What is Argyll-Robertson pupil?
associated with neurosyphilis (“prostitutes pupil”), “light-near dissociation” = pupils respond to accommodation but not light (accommodate, but don’t react)
What is Marcus Gunn pupil?
in swinging flash light test, when light is moved from normal eye to affected eye, the affected eye appears to dilate
Pupillary reflex
IN -> retina, CN II
OUT -> CN III
Corneal reflex
IN -> CN V
OUT -> CN VII
Tearing reflex
IN -> CN V
OUT -> CN VII
Jaw-jerk reflex
IN -> CN V
OUT -> CN V
Blink to Startle reflex
IN -> retina , CN II
OUT -> CN VII
What is required for normal function of larynx?
Valsava maneuver
What is epiglottitis?
Inflammation of the epiglottis, can result in difficulty breathing and swallowing; in severe cases can completely obstruct the airway
What is laryngocele?
Pathological obstruction and expansion of the laryngeal ventricle; may expand superiorly to the vallecula; infections may gain access to the fascial compartments of the neck
What is at risk for tracheostomy?
- jugulo-venous arch
- inferior thyroid veins
- thyroid ima artery
- left brachiocephalic vein, thymus (infants and children)
What is a cricothyrotomy? What is at risk?
access to the larynx is gained through a midline incision through the cricothyroid membrane (between the thyroid and cricoid cartilages); a thyroglossal duct or pyramidal lobe of the thyroid gland is at risk of injury
What is piriform recess?
A small depression on either side of the laryngeal inlet; common site for objects to get stuck (e.g. fishbone or a rupee); removal may injure the internal laryngeal nerve
What does the recurrent laryngeal nerve innervate?
All larynx muscles except cricothyroid muscle
What can occur if lesions of recurrent laryngeal nerve?
- lesions result in hoarseness
- in progressive lesions (compression by lymphadenopathy) abduction is lost before adduction
- in recovery adduction returns before abduction (likely because of bilateral innervation of the
transverse arytenoid muscles)
Non-recurrent laryngeal nerves…
in rare instances, the recurrent laryngeal nerve does not recur
in the normal pattern - in these cases, the nerve is in an abnormal position and is at risk of
iatrogenic injury
− On the right: associated with retroesophageal subclavian artery (dysphagia lusoria)
− On the left: associated with situs inversus or a right aortic arch
What does the internal laryngeal nerve provide?
Sensory innervation to the larynx above the vocal cords
What does the internal laryngeal nerve cause?
- injury results in aspiration of food/liquids
- may be injured in the removal of a laryngeal foreign body at the piriform recess
- this nerve is blocked (for intubation) by injecting anesthesia through the thyrohyoid membrane
What does the external laryngeal nerve innervate?
Cricothyroid muscle + inferior constrictor
What does external laryngeal nerve injury cause?
- injury results in monotonous speech
- paralysis of the cricothyroid muscle results in IL deviation of the thyroid cartilage (points
towards weak muscle; same pattern as genioglossus) + IL vocal cord is slack
What is dehiscence of Killian?
an unsupported region along the posterior pharyngeal wall between the crico- and thyropharyngeus muscles (both parts of the inferior constrictor)
What is Zenker’s diverticulum?
a pouch of pharyngeal mucosa that emerges through Killian’s dehiscence
All pharyngeal muscles are innervated by…
CN X except stylopharyngeus (CN IX)
Weakness/paralysis of pharyngeal muscles results…
Diminished gag reflex & dysphagia
What is Waldeyer’s ring?
A ring of lymphatic tissue, composed of lingual tonsil, palatine tonsils, tubal tonsils, pharyngeal tonsils (adenoids), and diffuse lymphatic tissue
What can enlarged palatine tonsils cause?
Block oropharynx and result in dysphagia
What can adenoid enlargement cause?
- enlargement in children results in “mouth breathing”
- adenoiditis refers to enlargement of the pharyngeal tonsils; can obstruct air flow from the nasal cavity and spread to middle ear (otitis media) via the pharyngotympanic tube
What does surgical removal of the palatine tonsil endanger?
External palatine vein, tonsillar artery (from facial artery) and CN IX
What is a peritonsillar abscess? What are its symptoms
a peritonsillar abscess refers to inflammation and infection around the palatine tonsils
- signs and symptoms include:
▪ fever, sore throat, muffled voice, trismus
▪ lymphadenopathy in Level II (see below)
▪ dysphagia, odynophagia
▪ otalgia
What are the complications of a peritonsillar abscess?
▪ airway blockage
▪ abscess rupture with spread into retropharyngeal space, mediastinum
▪ carotid artery erosion, jugular thrombus
▪ cavernous sinus thrombosis, meningitis
What is Ludwig’s angina?
Infection in the submandibular, sublingual and submental spaces (from a tooth infection); signs/symptoms include pain in the oral cavity and dysphagia
What is the motor innervation of tongue?
CN XII except palatoglossus (CN X)
What is the general sensory innervation of the tongue?
GSA innervation is from CN V (GVA to posterior 1/3 is from CN IX) - the terminal sulcus is the dividing line between anterior 2/3 and posterior 1/3
What is the SVA innervation of anterior 2/3 of tongue?
CN VII (lingual nerve; sensory ganglia = genticulate)
What is the SVA innervation of the posterior 1/3 of the tongue?
CN IX (sensory ganglia = inferior ganglion of CN IX)
What is the SVA innervation of the root of the tongue?
CN X (internal laryngeal nerve; sensory ganglia = inferior ganglion of X)
What is the autonomic innervation of the tongue?
Parasympathetics via chorda tympani (CN VII); sympathetics from superior cervical ganglion via external carotid plexus
How does tongue drain?
- tip - drains bilaterally to submental nodes (Ia)
- body (middle half; between tip and vallate papillae)
▪ center drains bilaterally to inferior deep cervical (jugulo-omohyoid) (IV)
▪ right and left portions drain to ipsilateral submandibular nodes (Ib) - root (posterior to vallate papillae)
▪ center drains bilaterally to superior deep cervical nodes (jugulodigastric) (II)
▪ right and left portions drain to ipsilateral superior deep cervical nodes (II)
What can obstructive sleep apnea result from?
a. hypotonia in oropharyngeal muscles: genioglossus, geniohyoid, tensor veli palatini and/or medial pterygoid muscles
b. enlarged tonsils, obesity (enlarged parapharyngeal adipose deposits)
c. craniofacial abnormalities (e.g. Pierre-Robin syndrome)
The submandibular gland wraps…
Around mylohyoid muscle, has a superficial and deep component
Wharton’s duct
Emerges from the deep portion of the gland and courses between the mylohyoid and hyoglossus muscles in the sublingual space in relation to the lingual nerve and CN XII - the duct is crossed twice by the lingual nerve; the duct empties at the sublingual caruncle
The majority of salivary calculi…
Are formed in the duct of the submandibular gland. Such stones are associated with peri-prandial pain and inflammation of the gland
The sublingual space is bound by…
The tongue (hyoglossus m; medial) and mylohyoid muscle (inferior)
What is within the sublingual space??
The sublingual space also includes the lingual artery (deep to hyoglossus m), lingual nerve, submandibular ganglion,
CN XII, the deep portion of the submandibular gland and Wharton’s duct
What is within the sublingual space??
The sublingual space also includes the lingual artery (deep to hyoglossus m), lingual nerve, submandibular ganglion,
CN XII, the deep portion of the submandibular gland and Wharton’s duct
Sialadenitis
Inflammation/painful swelling of a savilary gland
What is the parasympathetic innervation of salivary gland?
Via the CN VII and the chorda tympani nerve, which joins the lingual nerve in the infratemporal fossa. Preganglionic parasympathetic axons synapse in the submandibular ganglion. GVA innervation is also by CN VII, with
neuronal cell bodies in the geniculate ganglion
Innervation to connective tissue capsule of glands is…
GSA carried by CN V
Important regional nodes in head
- submental – drains tip of tongue, median part of oral cavity and central part of lower lip
- submandibular – drains the paranasal sinuses, oral cavity and tongue
- parotid – drains the middle ear (otitis media!) and external meatus (otitis externa!), eyelids,
conjunctiva, nasal cavity and nasopharynx - mastoid (retroauricular) – drains the external ear and external auditory meatus, temporal scalp
- suboccipital – drain posterior scalp
- retropharyngeal nodes – drains auditory tube, pharynx (tonsil + soft palate)
All lymph from head converges on…
Deep cervical lymph nodes and is returned to venous system at jugulo-venous angle
What is rhinitis?
- Mucosa includes cavernous (erectile) tissue – infections result in engorgement of the mucosa
- Infections can spread from the nasal cavity to the:
▪ anterior cranial fossa (through the cribriform plate)
▪ nasopharynx and pharynx
▪ tympanic cavity (through the pharyngotympanic tube)
▪ paranasal sinuses (through specific openings – see below)
▪ conjunctival sac (via nasolacrimal duct)
What is epistaxis?
Nosebleed
- The nasal septum has a rich vascular supply
- Nosebleeds commonly arise from the vascular network along the anterior 1/3 of the nasal septum (Kiesselbach’s
plexus/Little’s Area); includes contributions from the:
▪ Sphenopalatine artery (maxillary)
▪ Greater palatine artery (maxillary)
▪ anterior & posterior ethmoidal arteries (ophthalmic)
▪ Superior labial artery (facial)
What is a deviated septum?
- caused by MVA, fights, sports
- associated with an increased risk of sinusitis
- can result in compression of turbinates → inflammation, sinus infections
Pterygopalatine ganglion block
- done in cases of unexplained facial pain or to alleviate cluster headaches
- done via fluoroscopy: needle is placed through the nasal cavity, inferior to the middle concha and directed into the
pterygopalatine fossa through the sphenopalatine foramen
At risk: sphenopalatine artery
Frontal sinus
Commonly asymmetric, drains to middle meatus via frontonasal duct
Ethmoid sinus
drainage:
▪ posterior air cells – superior meatus
▪ middle + anterior air cells – middle meatus
- infections may erode through the medial wall of the orbit
- infections in the posterior ethmoidal sinus may affect the optic nerve (optic neuritis, blindness)
Maxillary sinus
- drains into the nasal cavity via the hiatus semilunaris; this aperture is typically small and is located along the superior aspect of the medial wall of the sinus → to fully drain this sinus, pt needs to tilt their head away from the affected maxillary sinus (if the right sinus needs to be drained, pt should lay on their left ear)
- the maxillary sinus is intimately related to the maxillary molars and superior alveolar nerve
Sphenoid sinus
- medial to cavernous sinuses; n of pterygoid canal runs along its floor
- drains through the anterior wall to the sphenoethmoidal recess
Subdural hemorrhage
damage to cerebral “bridging” veins (these veins carry venous blood from the cerebrum and traverse/bridge the subarachnoid space between the surface of the cerebral hemisphere and superior sagittal sinus) or less commonly emissary veins
- Most commonly damaged in “shaken baby syndrome”; elderly person after a fall, chronic alcoholic after a fall (“rattling” movement of the atrophied brain puts tension/stress on bridging veins)
- can be acute or chronic (on CT, fresh blood is bright white)
shape: banana hematoma
Epidural hemorrhage
damage to the middle meningeal artery (most commonly head trauma – skull fracture; trauma at pterion)
- “typical presentation” is loss of consciousness, alertness (“lucid interval”) then drowsiness/loss of consciousness
- less than 20% of pts demonstrate a lucid interval
- results in lens shape (“lemon”) hematoma on CT because the dura attaches to the skull along cranial suture lines; these attachment sites prevent blood from spreading anterior/posteriorly
Subarachnoid hemmorhage
bleeding from arteries comprising the circle of Willis
- result from ruptured aneurysm, arteriovenous malformation, trauma
- blood fills the subarachnoid space and fills the cisterns and sulci
- often associated with severe headaches since the free blood irritates the meninges
Subgaleal hematoma (extracranial)
- Commonly associated with vacuum extraction and forceps delivery (newborns)
- Results from rupture of emissary veins; blood accumulates between the epicranial aponeurosis and periosteum →
extends forward to orbital margins, backwards to nuchal ridge and lateral to temporal fossa (i.e. crosses suture lines) - Can result in lethal hypovolemia
Cephalohematoma (extacranial)
- Commonly associated with prolonged labor, vacuum extraction or forceps delivery (newborns)
- Results from rupture of small periosteal arteries; blood accumulates under the periosteum (between the periosteum
and skull); the hematoma is restricted by the periosteum and limited to individual bones of the skull (i.e. does not
cross suture lines)
Caput succendaneum (extracranial)
- Associated with birth trauma (vaginal delivery)
- Results from subcutaneous accumulation (between scalp and epicranial aponeurosis) of seroanguineous fluid (e.g.
lump or swelling); can cross suture lines - Usually self-limiting and resolves in ~48 hours
Cavernous sinus
- This “sinus” is actually a web-like network of veins through which pass the internal carotid artery (carotid siphon), branches of the internal carotid plexus and CN VI. Aneurysms arising from the internal carotid artery within the cavernous sinus will first impact the internal carotid
nerve and/or CN VI (s/s: headaches, partial Horner’s syndrome [see Neck #16] + diplopia)
What structures are close near the cavernous sinus?
CN III, IV, V1 & V2
What is a cavernous sinus infection?
an infection in the sinus that has often spread from the danger triangle of the face
can produce headache, papilledema, diplopia/ophthalmoplegia, visual deficits (blockage of retinal veins), pupillary deficits, ptosis and/or meningitis
The cavernous sinus also arise from…
Ear infection -> petrosal sinus
Tonsillar/peri-tonsillar abscesses dental/infections/paranasal sinuses
Engorgement of cavernous sinus can result in…
Chemosis (engorgement of conjunctiva)
Through basilar and occipital sinuses, the dural venous sinuses communicate with…
Batson’s plexus provides a route for the spread of abscess or metastasis into cranial cavity
Myopia
Focus of objects is in front of retina, nearsightedness (can’t see things that are far away)
Hyperopia
Focus of objects is behind the retina, farsightedness (can’t see things close up)
Retinal detachment
Separation of the neural retina from the pigmented epithelium; results in blindness in parts of the visual field
Macula
Contains the fovea centralis which only contains cones (at very high density) and is the area of highest visual acuity (center vision)
Glaucoma
Increased intraocular pressure from poor drainage (at canal of Schlemm) or over production of aqueous humor - impedes retinal blood flow and can lead to vision loss
Cataract
Opacity of lens
Optic disc
Where the axons forming CN II exit the eye and the central artery and vein enter/leave; no photoreceptors in this region - results in the physiological blind spot
Papilledema
Bulging of the optic disc from elevated intracranial pressure (tumor, etc)
Presbyopia
Age-related hyperopia resulting from loss of elasticity in the lens; results in a diminished ability to accommodation
Central artery of the retina
Is a terminal artery (i.e. no collateral support) arising from the ophthalmic artery
Occlusion of the central artery
Results in a sudden, painless loss of vision in the ipsilateral eye; funduscopic examination reveals a “cherry red spot” at the fovea from intact choroidal circulation (characteristic of Tay-Sachs & other metabolic storage diseases)
Most common cause of occlusion of central artery of retina
Atherosclerosis in the internal carotid artery
Amaurosis fugas
A painless, temporary loss of vision in one eye, “classically” described (~1/3 of pts) as a black curtain being pulled over one’s visual field; commonly from a vascular etiology (internal carotid, ophthalmic artery)
Inflammation in the lacrimal gland results in
Pain (from CN V)
Tear production is
CN VII (pterygopalatine ganglion with “hitch-hiking” on CN V); sympathetic innervation is from T1-4 (superior cervical ganglion→ internal carotid n → deep petrosal n)
Tears drain from…
Medial aspect of conjunctival sac via nasolacrimal duct, empties into inferior meatus
Cauliflower ear
Results from trauma to external ear (pinnae) with hemorrhage between cartilage and perichondrium; the cartilage becomes de-vascularized and undergoes fibrous transformation
Otitis externa
Infection within external ear canal
Sensory innervation of ear canal
CN V (auriculotemporal n)»_space; CN VII, IX, X
− CN VII: see Ramsay Hunt syndrome above
− CN X: the auricular branch of CN X is also known as Arnold’s nerve; it enters the mastoid canaliculus and exits at the tympanomastoid fissure to provide cutaneous innervation to the external ear and canal; it is associated with the ear-cough reflex
Sensory innervation to external aspect of tympanic membrane
CN V»_space; CN X
Lymphadenopathy of parotid
Superior deep cervical > mastoid nodes
Otitis media
Middle ear infection
Pain otitis media sensation
Sensory innervation of middle ear cavity and internal aspect of tympanic membrane: CN IX
Lymphadenopathy of otitis media
Parotid > superior deep cervical
Infection can spread
- via roof (tegmen tympani) – in children, through the unossified petrosquamous suture to middle cranial fossa (meningitis, brain abscess: temporal lobe > cerebellum); in
adults, through venous channels traversing this suture to dural sinuses (superior petrosal or petrosquamous sinuses) - via pharyngotympanic tube to pharynx
- to mastoid sinus (mastoiditis); can erode bone and enter middle cranial fossa or sigmoid sinus (=thrombus; s/s: fever, tenderness over the mastoid process, headache)
Chronic infections of middle ear can indanger
- chorda tympani (can also be damaged with perforation of the tympanic membrane!)
- CN VII (via dehiscence of the facial canal)
- tympanic nerve (from CN IX)
- internal carotid plexus (partial Horner syndrome)
Why are children more susceptible to middle ear infections?
the pharyngotympanic tube (in children) is shorter and more horizontal – and is thus more permissive of spread of infections from the nasopharynx
Somatic dysfunction of tensor veli palatine muscle results in
ear pain: this muscle functions to open the pharyngotympanic tube; chronic closure of the tube leads to build up of fluid and pressure in the middle ear cavity (=pain)
Gradenigo’s Syndrome
caused by the spread of otitis media to the petrous apex (temporal bone) and into the subarachnoid space; characterized by otitis media (with discharge
[otorrhea]), pain in the distribution of CN V (retro-orbital pain) and CN VI palsy
Myringotomy/tympanostomy
Perforation of the inferior (pars tensa; anterior»_space; posterior) aspect of the tympanic membrane to release pus from otitis media and/or place tubes for ventilation
Piercing the posterior-superior quadrant
the tympanic membrane endangers the incus,
stapes and chorda tympani n.
Hyperacusis
Paralysis of stapedius (CN VII injury) muscle resulting in increased perception of loudness
Conductive hearing loss
Dysfunction within the conductive mechanism (ruptured tympanic membrane, tympanosclerosis, cholesteatoma; otosclerosis, otitis media)
Sensorineural hearing loss
Hearing loss attributed to dysfunction of the inner ear (cochlear, hair cells), CN VIII or central auditory pathways
Presbycusis
Age-related sensorineural hearing loss
