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Questions and Answers
Where do the anterior ethmoidal cells open into?
Where do the anterior ethmoidal cells open into?
What is the purpose of the alar cartilage?
What is the purpose of the alar cartilage?
Which bony structure makes up part of the nasal septum?
Which bony structure makes up part of the nasal septum?
What is the function of the paranasal sinuses?
What is the function of the paranasal sinuses?
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Where is the nasolacrimal duct located?
Where is the nasolacrimal duct located?
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What do sinuses look like on X-rays?
What do sinuses look like on X-rays?
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What is the main venous drainage of the nasal cavity?
What is the main venous drainage of the nasal cavity?
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Where do the posterior ethmoidal cells open into?
Where do the posterior ethmoidal cells open into?
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Where do the sphenoidal sinuses open into?
Where do the sphenoidal sinuses open into?
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Where do the maxillary sinuses open into?
Where do the maxillary sinuses open into?
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Study Notes
Nasal Cavity Overview
- Nasal cavity consists of nasal vestibules, respiratory regions, and olfactory regions.
- Nasal vestibules are lined with skin and contain hair follicles, located just inside the nostrils.
- Respiratory regions are the largest part of the nasal cavity and lined by respiratory epithelium, with significant neurovascular supply.
- Olfactory regions are small spaces at the apex of each nasal cavity, lined with olfactory epithelium.
Skeletal Framework
- Comprises unpaired bones: ethmoid, sphenoid, frontal bone, and vomer.
- Paired bones include nasal, maxillary, palatine, lacrimal, and inferior conchae.
- The ethmoid bone forms the roof, lateral wall, and medial wall of both nasal cavities, containing ethmoidal cells.
Structural Boundaries
- Medial wall is covered by mucosa and forms the nasal septum, separating right and left cavities.
- Lateral wall features bone, cartilage, and soft tissue, supported by septal cartilage and alar cartilages with three conchae.
- Nasal septum consists of anterior septal cartilage and posterior vomer, with contributions from surrounding bones.
Nasal Cavity Regions
- Floor: Smooth and concave, mainly formed by the hard palate.
- Roof: Made up of the cribriform plate of the ethmoid; slopes posteriorly to choana.
Innervation
- Innervated by the olfactory nerve (I) for smell, exiting through the cribriform plate.
- Key nerves include the ophthalmic nerve (V1), with anterior ethmoidal nerve and maxillary nerve (V2) providing extensive lateral cavity innervation.
Vasculature
- Arteries include branches from the external carotid (sphenopalatine, greater palatine) and internal carotid (anterior and posterior ethmoidal arteries).
- Venous drainage follows arterial pathways: anterior regions drain to facial vein and posterior regions drain to pterygoid plexus.
Paranasal Sinuses
- Open into nasal cavities: named according to the bone containing them, lined with respiratory mucosa.
- Frontal sinuses are the most superior and innervated by the supraorbital nerve (branch of V1).
- Ethmoid cells located within ethmoidal labyrinth, innervated by ethmoidal branches of nasociliary nerve.
- Maxillary sinuses are the largest and fill the bodies of the maxillae, innervated by infraorbital branches of V2.
Nasal Meatuses and Recesses
- Inferior nasal meatus lies beneath the inferior concha, while middle and superior meatuses lie between their respective conchae.
- Sphenoethmoidal recess found above the superior concha; serves as an opening for sphenoidal sinuses.
Sinus Functions
- Sinuses produce mucus, serving immune defense and air filtration. The ciliated mucosa helps move mucus toward the choanae and throat.
Key Functional Structures
- Alar cartilage shapes the nostrils and maintains their form.
- Nasolacrimal duct opens into the inferior nasal meatus, playing a role in tear drainage.
Imaging Characteristics
- On X-rays, sinuses appear as large dark spots filled with air, confirming their normal state.
Venous Drainage
- Main venous drainage occurs via the pterygoid venous plexus, which is crucial for regulating blood flow from the nasal cavity.
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Description
This quiz covers the different regions of the nasal cavity, including boundaries, innervation, and irrigation. It also discusses the nasal vestibules, respiratory regions, and olfactory regions.
