Nose: Nasal Cavity Flashcards
Nasal cavity
2 cavities separated by nasal septum
Boundries
Each cavity opens
1. Anterior:
on face by anterior nasal aperture (nostril or anterior nares)
2. Posterior:
in nasopharynx by posterior nasal aperture (choana)
Roof
- Anterior sloping part
- Middle horizontal part
- Posterior sloping part
Anterior sloping part
Nasal and frontal bones
Middle horizontal part
Cribriform plate ethmoid
Posterior sloping part
Sphenoid body
Floor
Hard palate
Palatine process of maxilla anterior and horizontal plate of palatine bone posterior with incisive fossa and canals 2 cm behind its anterior end
Medial wall
Nasal septum
1. In front: septal cartilage
2. Below and behind: vomer
3. Above and behind: perpendicular plate ethmoid
4. Small posterior part: sphenoid rostrum
Lateral wall
Bones forming:
1. Below and in front: medial surface maxilla
2. Behind maxilla: perpendicular plate of palatine bone
3. Most posterior part: medial pterygoid plate
4. Upper part: medial surface of ethmoidal labyrinth
5. Upper anterior part: nasal frontal process of maxilla and lacrimal bones
Parts (3)
- Vestibule
- Atrium of middle meatus
- Nasal conchae and meatuses
Vestibule part
Small dilated part above nostril lined by skin containing:
1. Sweat glands
2. Sebaceous glands
3. Coarse hairs for filtration of dust
Atrium of middle meatus
Shallow depression above and behind vestibule continuous posterior with middle meatus
Nasal conchae
Lateral wall shows 3 bony projections with highly vascular mucosa:
1. Superior
2. Middle
3. Inferior
Superior concha
Smallest
Project from ethmoidal labyrinth
Middle concha
Largest
Project from ethmoidal labyrinth
Inferior concha
Largest
Separate skull bone
Conchae functions
- Increase surface area which magnifies air turbelance improving olfaction
- Increase humidity
- Warming of inspired air
Nasal meatus
Space below each conchae
Sphenoethmoidal recess
Space above superior concha
Middle meatus
Shows rounded elevation (bulla ethmoidalis) bounded below and in front by curved groove (hiatus semilunaris)
Openings
Openings of paranasal sinuses:
1. In sphenoethmoidal recess
2. In superior meatus
3. In middle meatus
Other openings:
1. In inferior meatus
2. Behind superior meatus
Sphenoethmoidal recess
Sphenoidal sinus
Superior meatus
Posterior ethmoidal sinus
Superior meatus
Posterior ethmoidal sinus
Middle meatus
- Middle ethmoidal sinus
- Frontal sinus
- Anterior ethmoidal sinus
- Maxillary sinus
Middle ethmoidal sinus
In bulla ethmoidalis
Frontal sinus
In ethmoidal infundibulum which opens in anterior end hiatus semilunaris
Anterior ethmoidal sinus
In ethmoidal infundibulum or in anterior end hiatus semilunaris
Maxillary sinus
In posterior end of hiatus semilunaris
Inferior meatus
Nasolacrimal duct
Behind superior meatus
Sphenopalatine foramen which opens in Pterygopalatine fossa
Nasal mucosa
- Olfactory mucosa
- Respiratory mucosa
Olfactory mucosa
- Lines roof, upper one cm of nasal septum, superior concha, and area above it
- Olfactory mucosa is yellowish, less vascular, and gives origin to olfactory nerve filaments
Respiratory mucosa
- Covers all parts of nasal cavity except olfactory region and vestibule
- Pink or red in color due to its high vasculature to allow rapid warming and moistening of inspired air
- Continuous with mucosa of paranasal sinuses, nasopharynx, and conjunctiva
Nerve supply
Smell senstion:
1. Olfactory (1st cranial) nerve
General sensation:
1. Anterior ethmoidal nerve
2. Infraorbital nerve
3. Lateral nasal (short sphenopalatine) nerves
4. Greater palatine nerve
5. Medial nasal (long sphenopalatine) nerves
Olfactory (1st cranial) nerve
From olfactory mucosa, 8-20 filaments passing through cribriform plate ethmoid, ending in olfactory bulb
Anterior ethmoidal nerve
Upper anterior art of lateral wall and septum
Infraorbital nerve
Lower anterior part of lateral wall and septum
Lateral nasal(short sphenopalatine) nerves
Upper posterior part of lateral wall
Greater palatine nerve
Lower posterior part of lateral wall
Medial nasal nerves
Posterior part septum
Atrial supply
- Anterior and posterior ethmoidal arteries (ophthalmic artery)
- Sphenopalatine artery (main artery 3rd part maxillary artery)
- Greater palatine (3rd part maxillary artery)
- Septal branch of superior labial (facial artery)
Anterior and posterior ethmoidal arteries
Upper anterior and posterior parts nasal cavity
Sphenopalatine artery
Most septum and lateral wall
Greater palatine artery
Lower anterior part septum
Septal branch of superior labial
Septum in vestibule region
Epistaxis area (little’s area)
- In lower anterior part of septum in vestibule region
- Area of anastomoses between sphenopalatine, greater palatine, and septal branch of superior labial arteries
- Bleeding from nose occurs from littles area 90%