Nose & paranasal sinuses Flashcards
What are the bony parts of the external nose?
- Superior: Nasal bones
- Inferior: Maxilla
What are the boundaries of the nostrils (naris)?
- Lateral (anterior): Major alar cartilage
- Lateral (posterior): Fibrofatty tissue
- Medial: Septal cartilage
What is the vestibule of the nose?
Extension of hairy skin into the proximal parts of the nasal cavity.
What are the components of the nasal septum?
- Anterior: Septal cartilage
- Posterior (superior): Perpendicular plate of ethmoid
- Posterior (inferior): Vomer
What are the components of the roof of the nasal cavities?
- Anterior:
1. Nasal bones
2. Nasal spine of frontal bone - Middle: Cribiform plate of ethmoid
- Posterior: Body of sphenoid
What are the components of the floor of the nasal cavities?
- Anterior: Palatine process of maxilla
- Posterior: Horizonal plate of palatine bone
What are the components of the lateral walls of the nasal cavities?
- Superior & middle conchi (ethmoid)
- Lacrimal bones
- Maxilla (frontal process)
- Inferior conchi (separate bone)
- Perpendicular plate of the palatine bone
What are the regions of the nasal cavity?
- Nasal vestibule
- Respiratory region: Largest part of nasal cavity. Lined with respiratory epithelium.
- Olfactory region: Apex of nasal cavity. Covered with columnar olfactory epithelium.
What are the main functions of the nasal conchi?
Increases musosal SA in nasal sinus to warm and humidify air.
What are the paranasal sinuses associated with the superior conchi?
- Sphenoidal sinus: Opens in the spheno-ethmoidal recess superior to the superior conchi.
- Posterior ethmoidal air cells: Opens into the superior meatus covered by superior conchi.
What are the paranasal sinuses associated with the middle conchi?
- Maxillary sinus: Opens into the floor of the semilunar hiatus in middle meatus.
- Frontal sinus: Opens into the anterior tip of the semilunar hiatus (ethmoidal infundibulum) via the frontonasal duct.
- Anterior ethmoidal air cells: Opens into the anterior tip of the semilunar hiatus (ethmoidal infundibulum).
- Middle ethmoidal air cells: Opens into the ethmoid bulla in the middle meatus, superior to the semilunar hiatus.
The opening of which duct is associated with the inferior meatus?
Nasolacrimal duct
What is significant about the opening of the maxillary sinus?
Located above the floor of the sinus, and so fluid collects much more easily and may lead to infections.
What are the relations of the maxillary sinus?
- Superolateral surface: Orbit
- Anterolateral surface: Upper molar teeth (inferior), face (anterior)
- Posterior surface: Infratemporal fossa
What type of epithelium is found within the air sinuses?
Ciliated columnar mucous secreting epithelium
What are the functions of the paranasal sinuses?
- Resonance chambers during speech
- Lightens bones of facial skeleton
What is the arterial supply to the nasal cavity?
- Sphenopalatine artery (maxillary artery)
- Anterior ethmoidal branch of opthalmic artery
- Labial branch of facial artery
What is the venous drainage of the nasal cavity?
- Facial vein
- Opthalmic vein
- Sphenopalatine vein
What is the nerve supply of the nasal cavity?
- Special sense: Olfaction supplied by olfactory nerves
- Somatosensation: Supplied by branches of opthalmic (V1):
1. Anterior ethmoidal
…and maxillary (V2):
- Lateral posteror inferior nasal
- Nasopalatine
- Anterior superior alveolar
- Infra-orbital
- Parasympathetic: Secretomotor to mucous secreting glands supplied by nerves from pterygopalatine ganglion
What is Little’s area?
Richly vascularised anterior aspect of nasal septum from which nose bleeds occur very frequently.
What is the division of the ears?
- External ear
- Middle ear
- Internal ear
What are the components of the external ear?
- Auricle (pinna)
- External auditory meatus
What are the features of the pinna?
- Helix
- Antihelix
- Crus of helix
- Crura of antihelix
- Concha
- Tragus
- Antitragus
- Lobule
What materials make up the pinna?
- Elastic cartilage
- Skin
- Fibrofatty tissue (lobule)
What is the structure of the external auditory meatus?
- 3cm long.
- Extends from the concha to the tympanic membrane, medially and anteriorly.
- Lateral 1/3 composed of cartilage (deficient posterosuperiorly where there’s just fibrous tissue).
- Medial 2/3 composed of bone (temporal bone).
What are the names of the glands found in external auditory meatus?
Ceruminous glands: Produces ear way
Which bone is the middle ear located in?
Petrous temporal bone
What are the boundaries of the middle ear?
- Roof: Bone (from petrous temporal) separating middle ear from middle cranial fossa
- Floor: Bone (from petrous temporal) separating middle ear from jugular fossa
- Lateral wall: Tympanic membrane
- Medial wall: Contains prominence of facial canal, oval window, round window, promontory (first turn of cochlea)
- Anterior wall: Contains the auditory (Eustachian) tube
- Posterior wall: Additus of mastoid antrum
What are the features of the tympanic membrane?
- Annulus: Cartilage attaching membrane to bone
- Pars flaccida: Thin, slack superior part of membrane
- Pars tensa: Thick, taut inferior part of membrane
- Umbo: Point of attachment of malleus onto tympanic membrane
Which direction does the cone of light always point in?
Anterior
What is the sensory innervation of the tympanic membrane?
- Outer surface: auriculotemporal nerve (branch of V3)
- Inner surface: Glossopharyngeal nerve [IX]
What is the nature of connectivity between the ossicles?
- Lateral process and handle of malleus attaches to the umbo of the tympanic membrane.
- Head of malleus articulates with body of incus.
- Long process of incus articulates with stapes.
- Base of stapes lies in oval window.
What are the muscles associated with the ossicles?
- Tensor tympani: Attached to the malleus and innervated by [V3].
- Stapedius: Attached to the stapes and innervated by [VII].
What are the external communications of the middle ear?
- Auditory (Eustachian) tube: Communication between anterior wall of middle ear and nasopharyx. Responsible for pressure equilisation.
- Aditus to mastoid antrum: Connection between posterior wall of middle ear and mastoid antrum. Involved in reducing resonance of sound.
What is the structure of the Eustachian tube?
- Proximal 1/3 (to middle ear): Bone
- Distal 2/3: Cartilage
What is the blood supply to the middle ear?
- Branches of internal carotid artery
- Branches of maxillary artery
- Occipital/posterior auricular artery
What is the innervation of the middle ear?
Tympanic plexus of tympanic nerve (branch of [IX])
What is the structure of the inner ear?
- Bony labyrinth refers the the bony cavities in which the sensory structure sit in.
- Membranous labyrinth: Ducts and sacs that make up the vesticulocochlear apparatus.
- Components of the apparatus include:
1. Cochlea: Hearing
2. Vestibular apparatus (saccule, utricle, semicircular canals): Balance
