COMPLETE NOSE ANATOMY - Bones, Sinuses, Muscles, Vascular Supply, Innervation

Summary

The nose, consisting of bony and cartilaginous components, serves essential functions such as filtering, humidifying, warming inspired air, and facilitating olfaction. Its structure includes the nasal root, bridge, and nostrils, while the internal nasal cavity is divided into the vestibule, respiratory region, and olfactory region. Paranasal sinuses, located around the nasal cavity, support functions like resonance and immune defense. The nose is richly vascularized and innervated by branches of the trigeminal and facial nerves. Understanding the anatomy and function of the nose is key to appreciating its role in respiratory and sensory processes.

Takeaways

• 😀 The nose consists of the nasal skeleton, housing the nasal cavity, which serves as the superior part of the respiratory tract.
• 😀 The nasal cavity has multiple functions: trapping pathogens, humidifying and warming inspired air, and draining the paranasal sinuses and lacrimal duct.
• 😀 The external nose includes the nasal root, bridge, dorsum nasi, apex (tip), nares (nostrils), and the nasal columella separating the nares.
• 😀 The skeletal structure of the external nose is made up of both bony (nasal bone, frontal bone, maxilla) and cartilaginous components (lateral, alar, and septal cartilages).
• 😀 Muscles like the procerus and nasalis contribute to facial expressions such as lowering the eyebrows and flaring the nostrils.
• 😀 Sensory innervation to the external nose is provided by the trigeminal nerve, while motor innervation for facial expression comes from the facial nerve.
• 😀 Blood supply to the external nose comes from branches of the ophthalmic and maxillary arteries, while venous drainage follows into the facial vein and jugular vein.
• 😀 The paranasal sinuses—frontal, maxillary, sphenoid, and ethmoid—serve to humidify air, lighten the head, support immune defense, and add resonance to the voice.
• 😀 The nasal cavity is divided into three sections: the vestibule, respiratory region, and olfactory region. The respiratory region is lined with respiratory epithelium.
• 😀 Nasal conchae (turbinates) increase the surface area of the nasal cavity, aiding in air humidification and slowing airflow for better air quality processing.

Q & A

What are the primary functions of the nasal cavity?

The nasal cavity primarily serves to trap and remove pathogens and particulate matter from inspired air, warm and humidify the air, and drain the paranasal sinuses and lacrimal duct.

What structures make up the external nose?

The external nose consists of both bony and cartilaginous components, including the nasal bone, part of the frontal bone, and part of the maxilla. The cartilaginous component is made up of two lateral cartilages, two alar cartilages, some smaller alar cartilages, and the septal cartilage.

What are the names of the muscles that control movement in the external nose?

The muscles responsible for movement in the external nose include the procerus muscle, nasalis (which has a transverse and an alar part), and the depressor septi nasi.

How does the nose receive sensory innervation?

The nose receives sensory innervation primarily from the trigeminal nerve, with the external nasal nerve (a branch of the ophthalmic nerve) supplying the skin of the dorsum and nasal vestibule, and the infraorbital nerve (a branch of the maxillary nerve) supplying the lateral aspects.

What is the role of the paranasal sinuses?

The paranasal sinuses serve to humidify inspired air, lighten the head, support immune defense, and add resonance to the voice. They are located within the frontal, maxillary, sphenoid, and ethmoid bones.

Where do the paranasal sinuses drain into the nasal cavity?

The frontal, maxillary, and anterior ethmoidal sinuses drain into the middle meatus through a crescent-shaped groove called the semilunar hiatus. The posterior ethmoidal sinuses drain into the superior meatus, while the sphenoid sinus drains into the posterior roof.

What are the three sections of the nasal cavity?

The nasal cavity is divided into three sections: the vestibule, respiratory region, and olfactory region. The vestibule is the area within the nostrils, the respiratory region contains nasal conchae and respiratory epithelium, and the olfactory region is responsible for the sense of smell.

How do the nasal conchae affect airflow?

The nasal conchae increase the surface area of the nasal cavity, which enhances the amount of inspired air coming into contact with the walls. They also disrupt fast laminar airflow, making it slow and turbulent to allow air to stay in the cavity longer and become humidified.

What is Little's area and why is it important?

Little's area, also known as Keisselbach's area, is located in the anterior portion of the nose and is a spot where several arteries anastomose. It is significant because it is a common site for nosebleeds (epistaxis).

What is the role of the olfactory nerve in the nasal cavity?

The olfactory nerve carries special sensory information related to the sense of smell. It passes through the perforations in the cribriform plate of the ethmoid bone to reach the olfactory bulb in the brain.