Lecture 9 - Nasal cavity Flashcards
Why important
- Fractures here
- need to examine, can get anterior or posterior bleeding (epistaxis)
- Anterior - most common
- Nasal polyps
- Nasal septal haemotoma- if dont send to surgeon, pateint can loose septum and both cavities will become one
Regions of nasal cavity
Olfactory region - Sits on cribiform plat and olfactory nerves run within these holes (for smell)
Respiratory regions - rich neurovascular supply, lined by resp epithelium - ciliated and mucous cells
Nasal vestibule - small space, lined by skin and has hair
nasal septum - in middle (medial wall)
Floor - hard palate
External nose
- Plastic surgeons manipulate this
- formed by different cartilages -lateral process of septal cartilage, superior margine of septal cartialge, major alar cartialge, minor alar cartialeg
Made of nasal bone superiorly, and cartilage inferiorly
Spetum of nose
formed by cartilage and the bony part
Floor
Roof
Floor - horizontal plate of palatine bone, palatine process of maxilla
Roof - nasal bones, nasal spine of frontal bone, cribriform plate, alar of vomer, medial plate of pterygoid
Ethmoid bones Exam - dont need to know much detail, but how it contributes to bony structures of nasal cavity - in a coronal section
Sinuses sitting above and below - drain into the nasal cavity and openings lie within these bones
- cribriform plate - olfactory nerves go into nasal cavity
- lots of processes and cracks - eventually form ridges and this is where sinuses drain
Medial wall - clinically relevant - need to know details for exam
medial wall - if there is trauma, this is what will get damaged
- septal cartilage - examine this if someone comes in form trauma - a bunch of arteries here - if break arteries get septal haemotoma - if dont drain this, then lose septal cartialge and will lose external nose
- perpendicular plate of ethmoid bone
- Vomer
- nasal crest of maxilla bone
- palatine bone
Lateral wall
- rewatch this part
Important - for sinusitis
- major alar cartialge, lateral process of septal cartilage
- nasal bone
- frontal bone
- ethmoid bone - superior, middle and inferior conchae
- lacrimal bone
- perpendicular plate of palatine bone
- frontal process of maxilla
(sagital cut - can see this)
- Sinuses drain to chonchae - so important - need to know them in detail
- mucosa sits on top
- if doign surgery - sometiems need to cut the concahe to see further - can see opening of ethmoidal sinuses , ethmoidla bulla
Paranasal sinuses
Sphenoid sinus
as you grow, erosion in the structure - makes skull lighter and sinuses form
Sphenoid sinus - starts at day 1
-can remove pituitary tumour through sphenoid sinus
Drainage of sinuses and ethmoid cells
Sphenoid sinus - opens above the superior tubernate - spehnoethmodial recess
Within superior and middle - posterior ethmoidal sinus drains here
-Posterior ethmoidal sinus drains here
Between middle and inferior turbinates - middle ethmoidal into ehtmoidal bulla , frontal sinuses and anterior ethmoidal sinus, and maxillary sinus opens into semilunar hiatus
Inferior to inferior tubernate
-nasolacrimal duct opening
(when you cry you get a runny noise)
For exam - important - septomedial wall, lateral wall where sinuses drain, and understanding the bony structure
Gateways
Maxillary artery goes through - Sphenopalatine foreamen (posterior nasal bleeding)
-also have sphenopalatine artery
Foreamen cacum
Cribriform plate
Sphenopalatine foramen
Incisive canal
Anterior opening of nasal cavity
Posterior opening of nasal cavity
Small foreamen on pterygoid plates
Epitaxis
someone coming with trauma - miss haemotoma - then loose the front of the nose
-if dont understand the blood supply of the nasal cavity, (if dont know if anteiror or posterior) and wait to long, pateint may die
-postreior epitaxis - can tasete blood as well as it comign out of nose
Blood supply to nasal cavity - NEED TO KNOW FOR EXAM
Posterior - most important contributor - sphenopalatine artery (continuation of maxillary artery)
-sends branches and anatosmoses with anteiror branches
Anterior - normally not as bad
- arteries comign from external and internal bleeding
- if BP increases - then get cranial nerve bleed here - posterior and anterior ehtmoidal - when it gets to the cavity, may run over the walls
- meet with other branches that contribute to anteroir part
internal carotid - opthalmic - ehtmoid
The little area
- terminal part of greater palatine, contrinutes with anteiror ehtmoidal artery, and posterior ethmoidal and labial artery –> anastomose - this area called little area
- most commonly get bleeds in this part
- block anterior part of nasal cavity to stop bleeding
Venous drainage
Lymph nodes
- always drain to submandibular gland - go to deep cervical
- infection in nose/cancer - get large submandibular gland
Viens run with the arteries, but have a nasal vein running through foreamen caecum
-nasal vein can get back to cranium - get meningitis
