Anatomy, Physiology, & Histology Flashcards
acoustic antenna; transmits sound waves to middle ear structures.
External ear
impedance matching or transferring incoming vibrations from large low impedance tympanic membrane to smaller but high impedance oval window
Middle ear
impedance matching or transferring incoming vibrations from large low impedance tympanic membrane to smaller but high impedance oval window
Middle ear
site for acoustic vibrations from mid ear transmitted to perilymph; this set in motion the nerve endings and transform vibration to electric impulse of hair cells for hearing
Inner ear
The reason why during PE, to visualize the tympanic membrane using an otoscope, you should
“S” shaped, to protect against injury “S” shaped, to protect against injury
Seen as deficiency or a fracture line in the cartilaginous part
Clinical significance: gateway for disease to pass from external auditory canal to the periparotid and neck spaces
Infections from the parotid and superficial mastoid can enter the canal and vice versa
Fissure of Santorini
Route of communication between the external ear and infratemporal fossa
Route for tumors and infection to spread
Foramen of Huschke
Supplies lateral surface thru the anterior auricular branches
Superficial temporal artery
Supplies the medial surface thru the auricular branches
Posterior auricular artery
Supplies medial surface thru the auricular branches
Occipital artery
labyrinthine artery or internal acoustic artery from basilar artery
Internal Ear
Alderman or Arnolds nerve -> cough reflex when EAC is stimulated
Jacobsons nerve
CN X and CN IX
Normal findings of a Tympanic membrane
semi-translucent, pearl white oval, presenting obliquely 55 degrees with canal floor
1.0cm2, superoinferiorly, 8mm anteroposteriorly
Umbo-center of TM
Triangular part above the anterior and posterior malleolar folds, common site of retraction points
Pars Flaccida (Shrapnell’s membrane)
Portion below the malleolar fold tensed by the manubrium of the malleus
Pars tensa
Fibrocartilaginous ring which supports the tympanic membrane; deficient superiorly at the notch of Rivinus
Annulus fibrosus
Ear ossicle definition
First bones to be fully ossified during development and are essentially mature at birth
Covered with the mucous membrane lining the tympanic cavity; they lack a surrounding layer of osteogenic periosteum
Muscles associated (both dampen or resist movements of the auditory ossicles
Eustachian Tube anatomy and physiology
Lined with mucous membrane; connects middle ear to back of the throat (nasopharynx)
Upper 1/3 near middle ear à bony about 12 mm • Second part of the ET near nasopharynx is cartilaginous
Equalizes air pressure
Normally closed except during yawning or swallowing
Inner Ear (Labyrinth): Bony Division
Semi-circular canals (SCC) à three canals that lie at the right angle to one another and about 2/3 of a circle
Lateral or horizontal: not really horizontal but 30 degrees to the horizontal; nonampullated end opens to posterior wall of vestibule
Superior joins free posterior at the crus communis before entering the vestibule in the middle of the posterior wall
Posterior
Inner Ear (Labyrinth): Vestibule divison
Ovoid chamber that measures 5 mm long, 5 mm high and 3 mm deep; central area which receives several openings
Anteriorly: scala vestibule of cochlea
Posteriorly: five openings of the semicircular canals
Lateral wall: opening of the oval (fenestra vestibule) and round (fenestra cochlearis) windows
Inner Ear : Oval Window and Round Window
Oval Window: Located at the footplate of the stapes
When the footplate vibrates, the cochlear fluid is set into motion
Round Window: Functions as the pressure relied port for the fluid set into motion initially by the movement of stapes in the oval window
5 Bones of the Nose
o Maxilla
o Frontal bone
o Nasal bone
o Vomer
o Ethmoid
External nose: Bony Vault
Bony vault ->immobile; most superior
Frontal process of maxilla
Paired nasal bones
Nasal spine of frontal bone
Perpendicular plate of nasal bone
External nose: Bony Vault
Bony vault ->immobile; most superior
Frontal process of maxilla
Paired nasal bones
Nasal spine of frontal bone
Perpendicular plate of nasal bone
External nose: Cartilaginous
Slightly movable and made up of:
Paired upper lateral nasal cartilage
Paired lower nasal cartilage (greater alar cartilage)
Lesser alar cartilage § Accessory alar cartilage (sesamoid cartilage)
Septal cartilage
Help regulate respiration
Nasal valve of Mink
Internal Nose: Roof
o Nasal bone
o Under nasal spine of frontal bone
o Cribiform plate of ethmoid
o Undersurface of sphenoid bone
What are the sinuses opening of the middle meatus
Anterior ethmoidal cells
Middle ethmoidal cells
Maxillary sinuses
Bulla ethmoidalis
Anterior ethmoidal cellls and the frontal sinuses openins in the?
Anterior part of the meatus
Middle ethmoidal cells opening
Above the bulla ethmoidalis or hiatus semulinaris
Maxillary sinuses opening
Posterior part of the hiatus semilunaris
Osteometal Complex: Anatomy and Physiology
Area in the lateral nasal wall where ostia or opening of paranasal sinus except for sphenoid sinus (mid meatus)
(+) free airflow and mucicilliary drainage
Osteomeatal Comlex composed of?
o Uncinated process
o Semilunar hiatus
o Frontal recess
o Ethmoid bulla
o Ethmoid infundibulum
o Maxillary sinus ostium
Nasal Septum: Bony parts of the septum are formed by the?
o Posteroinferiorly by the vomer
o Posterosuperiorly by the perpendicular plate of ethmoid
o Nasal spine of frontal bone joins ethmoid plate
o Rostrum of sphenoid between the vomer and ethmoidal plate
o Nasal crest of the two maxillae and palatine process
Nasal Septum: Cartilaginous Part
• Formed by quadrilateral cartilage
• Attached to a perpendicular plate of ethmoid bone posterosuperiorly
• Anterior border of vomer
• Internasal crest superiorly
• Nasal crest of maxilla and anterior nasal spine inferiorly
• Upper nasal cartilage attached to anterosuperior border of septal cartilage
Mucosa of the nose: Anterior Vestibular region lined by?
Stratified squamous epithelium; end at mucocutaneous junction
Respiratory portion of nasal mucosa lined by?
Pseudostratified columnar ciliated
Mucosa is firmly adherent to perichondrium and periosteum
Olfactory mucosa of the nose
Occupies olfactory region on nose -> extends over upper part of septum and adjacent to lateral wall to superior turbinates
Yellowish color
main supply; branch from internal maxillary artery and Divides to lateral nasal and long septal branch
Sphenopalatine artery
Branch of ophthalmic artery and Supply upper part of lateral wall and upper part of septum
Anterior and Posterior ethmoidal artery
Enter thru the inclusive canal to the nose and supplies the anteroinferior part of the septum and adjacent areas of the floor and lateral wall
Greater palatine artery
Supplies the septim and nasal alae
Superior labial branch of the facial artery
Arterial blood supply form anastomosis at the anteriorinferior portion of the septum also called as little’s area frequent site of bleeding
Keissel-Bach’s Plexus
Anterior Epistaxis comes from?
• Greater palatine
• Anterior ethmoid
• Sphenopalatine
• Superior labial
GAAS
Woodroofs plexus (Posterior epistaxis) comes from?
o Internal maxillary veins
o Sphenopalatine (from maxillary artery)
o Ascending pharyngeal (from external carotid)
ISA
Paranasal sinuses parts
They are hollow within several facial bones and named:
o Maxillary
o Sphenoid
o Frontal
o Ethmoid
Paranasal sinuses definition
•Humans have 12 cavities along roof and lateral aspect of air space varying in number, size, shape, and symmetry
• All paranasal sinuses are lined with modified respiratory epithelium that produces mucous and having cilia
• Essential sinuses are air filled
• Only Maxillary sinus are present at birth – the rest appear in early childhood
Maxillary Sinus or Anthrum of Highmore
• Pyramidal cavity in maxilla
• Divided into small spaces by bony septa
• Roof from floor of orbit
• Floor below level of nasal cavity and from alveolar process of maxilla
• Contains anterosuperior dental vessels and nerves
• Roots of premolar and molar teeth may project to sinus cavity
MAXILLARY SINUS OR ANTRUM OF HIGHMORE Medial wall and Posterior wall
Medial Wall:
o Nasal surface of maxilla
o Perpendicular plate of palatine bone
o Maxillary process of inferior turbinate
o Uncinated process of ethmoid
Posterior Wall:
o Posterior surface of maxilla
MAXILLARY SINUS OR ANTRUM OF HIGHMORE Opening and Capacity
• Opening of maxillary sinus is posterior part of hiatus semilunar between bulla ethmoidis
• Capacity of sinus varies: 15 – 30 mL
FRONTAL SINUS Anatomy
• 2 in number; unequal size
• Develop in frontal bone
• Average capacity of sinus: 7 mL (adults)
• Supplied by supraorbital nerve and vessels
FRONTAL SINUS Pathophysiology Colleration
• Anterior wall and floor of sinus have marrow containing bone; osteomyelitis can develop at any age
• Floor of sinus forms part of roof of the orbit; posterior wall forms anterior boundary of anterior cranial fossa -> infection of sinus can drain via frontonasal duct which opens in middle meatus
SPHENOID SINUS Anatomy
• 2 sinuses unequally divided by septum
• Develop in the body of sphenoid bone
• Superiorly related to frontal lobe and olfactory tracts
• Above and posteriorly lies the pituitary gland
• Laterally related to optic nerve and cavernous sinus
• Opens in anterior wall in sphenoethmoidal recess
Larynx: Location and Main Function
• Located at level C4 or C5 to C7
• Main function: separate aerodigestive tract to 2 distinct parts
• Voice box
Suprahyoid muscle group
• Stylohyoid, digastric, genohyoid, stylopharyngeus (elevates larynx)
• Intrinsic muscles
• Cricothyroid: only muscle outside larynx
• Post-cricoarytenoid: only abductor of vocal cord (safety muscle)
Branch of superior thyroid artery from external carotid artery
Superior laryngeal artery
From inferior thyroid artery from subclavian artery
Inferior laryngeal artery
Laryngeal lymphatics
o Supraglottic area: drain to deep cervical node in carotid bifurcation
o Subglottic area: drains to LN at upper trachea to deep cervical and superior mediastinal node
o Glottic area: devoid of lymphatics
Child has diminished hearing on R ear thru out the day which started 2 weeks PTC; no other SSX and improves by swallowing Impacted cerumen
Impacted cerumen
A 40 y/o female px complains of vertigo, hearing loss and tinnitus
Meniere’s Disease
Px complains of fever, pain and nasal discharge
Acute Otitis Media
A px complains of chronic, foul-smelling ear discharge
Chronic Suppurative Otitis Media
A 23 y/o px complains of watery ear discharge, ear pain on R ear; 5 days PTC fever, 4 days PTC clear nose discharge and stuffy nose; 2 days ptc pain
Viral in etiology (AOM)
Unilateral foul-smelling, sudden loss of hearing
Foreign Bodies
Arteries that comprise the Woodruff’s plexus (located posterior to the middle turbinate)
• Sphenopalatine artery (branch of maxillary)
• Ascending pharyngeal artery (branch of ECA)
• Internal maxillary veins
• Posterior septal arteries
Dysfunction in sense of smell (you smell an object differently)
Parosmia
Battle Sign of ear signifies
Hematoma
A test to diagnose mastoiditis and needs Xray to confirm
Three-Finger Test:
(Index, middle and thumb)
Index- over mastoid
Middle-over ear concha
Thumb- apply pressure over mastoid process
Question about Rinne and Weber Test
CHL:
• Rinne BC>AC
• Weber: lateralizes to impaired ear
SHL:
• Rinne: AC>BC (transduction and sound conduction are both affected)
• Weber: lateralized to the normal ear
Brodzky score
Grade 0: tonsils in fossa or removed
1+: <25% oropharynx occupied
2+: 25-50%
3+: 50-75%
4+: >75%
Mallampati Score
Class 1: soft palate, entire uvula, faucial pillars
Class 2:soft palate, entire uvula
Class 3: soft palate, base of uvula only
Class 4: only hard palate visible
Function of cochlea
Transduction – convert sound waves into mechanical vibrations of eardrum and ossicles then these vibrations get sensed by crista hair cells and turned into action potential
Function of cochlea
Transduction – convert sound waves into mechanical vibrations of eardrum and ossicles then these vibrations get sensed by crista hair cells and turned into action potential
Blood supply of external ear
• Posterior auricular
• Superficial temporal
• Occipital artery
• Maxillary artery (deep auricular branch)
*all are branches of ECA
Branch of CN X; Cough reflex; supplies skin of external acoustic meatus
Arnold’s Nerve
Branch of CN IX, caused referred pain (pain from an abnormality in throat or nasopharynx is referred to the ear
Jacobson’s nerve
Layers of tympanic membrane
• Outer epidermal layer
• Middle fibrous layer
• Inner mucosal layer
