Anatomy of the Human Nose: All About Human Nose
Table of contents
A human nose is the part of the respiratory region that is placed in the centre most front of a human face. To know the anatomy of the nose, its functions must be understood first. The basic function of the nose includes to breathe in and out air, and to smell.
The nose is the only means of getting warm humidified air into the lungs. It is the only organ for filtering out molecules in inspired air, and it also plays a part to provide first-line immunologic safeguard by channelizing the contact between inspired air and mucous-coated membranes that consists of immunoglobulin A (IgA). Inspired air is fetched high into the nasal cavity to bring in contact with the olfactory nerves, thus giving the sense of smell, which is closely related with the taste sensation. Debiliated functioning of any of these systems can prompt symptoms of nasal impairment (eg, sinus infections, congestion, postnasal drainage, headaches, facial pressure).
Endoscopic view from olfactory nerves of right nasal passage.
Understanding of the co-relation between the upper and lower airways has risenand this this concept is now referred to as the unified airway. and whatever actions affect one also affect the other. Thereby, alterations in the physiology of the nose and paranasal sinuses can and will have an effect on the lower airways and vice versa.
The nose is an intricate integrant of the facial anatomy that is made up of myriad of structures. Here we will go from top to bottom and explain each of the components for a thorough awareness of the composition of a human nose.
Internal Structure of Nose
The bony part of the nose only constitutes to the upper 3rd of the nose bridge. Tangibly, it is held accountable for the length of the nose. It also gives support to the upper portion of the nose.
The whole of the nasal cavity is fringed with a surface composed up of glands and epithelial cells that forms mucus. This mucus helps to keep the inside of the nose damp, traps allergens and other tiny bits or particles and helps to keep the air moist that you breathe in. Heaps of cilia constantly keep moving the mucus layer across the mucosal surface, sweeping toxic particles out of the nose in the process. In this manner, the nose is an air purifier that cleanses air before it reaches the lungs.
At the peak of the nasal anatomy is the nasopharanx, which accomodates lymphoid tissue called the adenoids., the nasopharanx is also attached to the ears through the Eustachian tubes.
A portion known as the choana connects the nasopharanx to the right and left portions of the nasal cavity, which is of the oral cavity and toughened palate. Situated under the skull base and intracranial compartment, it is divided by the septum.
The septum consists of bone in the back and cartilage in the front and middle portions. The bony part, which remains fixed, is composed of the perpendicular maxilla bone, the ethmoid bone and the vomer bone. The septal cartilage, which is moveable, is bordered by another portion of cartilage known as the lateral nasal cartilage.
The lateral nasal walls, or sidewalls, each comprises of 3 finger-like structures called turbinates, which are made of bony core covered with mucosa and soft tissue. The turbinates govern nasal airflow and render mucosa surface area.
The biggest turbinate portion is known as the inferior turbinate. It is situated along the complete length of the nasal sidewall, subsequent to the nasal floor. The middle turbinate is situated next to the septum and stretches into the central nasal cavity. It is connected to the sidewall at the back, right above the inferior turbinate. The smallest of the 3 turbinates is known as the superior turbinate. It is situated above and at the back of the middle turbinate and links to the skull base and nasal wall.
Right below the septal cartilage is the larger alar cartilage, which creates the medial and lateral walls of the nostrils, and below this are 4 lesser alar cartilages.
Near the tip of the nose are the nostrils and the columella – the strip of skin between the nostrils. The portion of the nostrils that attach to the cheeks is called the alae.
Your nose also has 4 kinds of muscles known as elevators, compressors, depressors, and dilators. They are linked by a framework known as the nasal superficial masculoaponeurotic system.
External Structure of Nose
The facet of the human nose comprises of a frontal section consisting of the glabellas, alar sidewalls, nasion, and tip points; a basal section comprises of the nostrils, columella, infra tip lobule, and soft tissues; and two other section termed as oblique and latter sections. The internal framework of the nose, specifically its cartilage and bone structure, is accountable for the physical/ visible feature of the nose.
The nose’s exterior anatomy includes the nasal cavity, nerves, paranasal sinuses, lymphatics and blood supply. The external area of the nose involves the dorsum that travels down the middle and the apex at the tip of the nose and the root (between the eyes). Two openings known as nostrils (nares) permits air to enter in. They are fractioned by the nasal septum (dividing wall of bone and cartilage), and the parts that encompass the nostrils are known as the alae (ala singular).
The nose has a bony part that is produced by the bony nasal septum, parts of the maxillae, palatine, the nasal bones, and frontal bones. The cartilaginous part of the nose is created by 2 alar cartilages, 2 lateral cartilages, and a septal cartilage.
The paranasal sinuses
The paranasal sinuses are air-packed cavities in the frontal, maxilla, ethmoid, and sphenoid bones. They are bordered with a mucosal membrane and have little openings into the nasal cavity:
- Maxillary sinus: This sinus is positioned in the body of the maxilla at the back of the cheek area right above the roots of the molar and the premolar teeth. It is formed like a pyramid. It opens into the nasal cavity by way of the semilunar hiatus.
- Frontal sinuses: Constructed within the frontal bone, each of these sinuses is triangular in shape and goes atop of the medial end of the eyebrow and retrogrades to the orbit. They open into the nasal cavity by way of the semilunar hiatus.
- Ethmoid sinuses: The anterior, posterior and middle ethmoid sinuses are positioned in the ethmoid bone in between the nose and the eye. The anterior sinus opens into the nasal cavity via the infundibulum, the posterior sinus opens into nasal cavity via the superior meatus, and the middle sinus opens into the ethmoidal bulla.
- Sphenoid sinuses: These sinuses are present in the sphenoid bone, with each opening into the sphenoethmoid recess.
Nerves, blood vessels, and lymphatics of the nose
Nerve supply to the external nose is rendered by the external and the infratrochlear nasal branches of the infraorbital branch of the maxillary nerve and the ophthalmic nerv, both of which are constituent of the trigeminal nerve (CN V). The olfactory nerves (CN I) go through the cribiform plate of the ethmoid bone. Basic sensory innervations of the paranasal sinuses and nasal cavity are from the maxillary nerve (CN V2) and the ophthalmic nerve (CN V1).
Blood is transported to the external part of the nose by divisions of the maxillary arteries and ophthalmic. The skin of the septum and ala are transported by the facial artery. Blood is obtained in the sinuses and nasal cavity walls by divisions of the maxillary artery. The most crucial is the sphenopalatine artery, which with a division of the superior labial artery. .
Nasal Structure and Rhinoplasty
Rhinoplasty pertains to regulating, shaving, summing to and/or otherwise modifying the structures of the nose. The basic components of the nose that are changed during rhinoplasty procedures are as follows:
- Bone – The bone can be cautiously and mildly shaved down to lessen the height of the nasal bridge.
- Cartilage – In rhinoplasties, this is the most altered part of the nose. To lower down the size of the nose in any particular area, cartilage can be tactfully sutured without sacrificing the support structure. In case to increase the size of the nose or give more structural support, grafts can be formed from existing cartilage in the patient’s nasal septum, rib cage or ear.
- Nostrils – The nostrils can be made to contract in size by making an incision right along the alar base and getting the width inwards.
- Skin – Thick nasal skin is decreased by thinning the fatty tissue below the skin.
Tests of nasal physiology include studies of airflow, olfaction and ciliary function.
Rhinomanometry is conducted to measure nasal airflow and total nasal area at the time of exclusive nasal breathing. Differential pressure quantifications are attained by locating a nasal catheter into the nasopharynx.
Acoustic rhinometry is a modern method for assessing the cross-sectional area of the nose and the volume of the nasal cavity by evaluation of reflected sound during a short stoppage of nasal breathing. This method has been approved and is also helpful for documenting alterations in nasal patency caused by surgical or pharmaceutics interventions. The technique is fast and minimally invasive
Radiologic imaging with MRI or CT also can evaluate the cross-sectional area of nasal passages
The saccharin test assesses ciliary function by gauging the time it takes for a drop of saccharin to be tasted behind the throat when put on to the anterior tip of the inferior turbinate.
Various tests of olfaction are available, but the University of Pennsylvania Smell Identification Test (UPSIT) is often commonly. The UPSIT is a 40-item scratch-and-sniff test and is given credence by age and sex.