The sinuses of the skull are cavities that are filled with air. They are located in the middle of the bones of the skull in the facial region. The structure of the nose and its sinuses is unique, but, despite this, all the internal structures of the body are closely interconnected.
Anatomy and structure of the nasal cavity
The nose is an organ consisting of the external and internal departments, both of which are a cavity. The basis of the outer section is the bone-cartilage joint, located in the form of a pyramid. The outer upper layer of the nose is covered with a layer of skin. This part of the nose includes the bridge of the nose, back and wings that form the openings of the nostrils.
The nasal cavity is located between the mouth and the front side of the cranium. The side walls of the nose are in contact with the upper jaw and ethmoid formations. Both parts of the nose, which are interconnected by a septum, communicate with the environment through nostril openings.
The inner side of the nose consists of the upper, middle and lower shells. Outwardly, they look like horizontal plates arranged parallel to each other. At the bottom of each shell there is a nasal passage, but not one of them is connected by a septum located in the middle of the nose. The space remaining between the shells has one common nasal passage. The inside of the nasal cavity is covered with mucous membrane.
Both parts of the nose are surrounded by chambers that are filled with air. Internal communication is made through narrow holes, the diameter of which is very small. When the nose is blocked, the sinus swells and closes the communicating hole.
The structure of the paranasal sinuses
In connection with the peculiarities of location, the sinuses can be divided into two main groups:
- Front This group includes the frontal bone, maxillary sinuses, as well as the front and middle parts of the ethmoid bone.
- The back. This group includes the sphenoid sinus and the posterior ethmoid bone.
Thanks to the division into groups, the doctor has the opportunity to correctly diagnose, since the inflammation that proceeds in different departments will differ from other pathological signs and symptoms.
Nose function
All parts of the nose have a number of their own characteristics. Each part is covered with mucous membrane. It is important that the latter is not damaged. The nose in the human body plays a rather important role, because through it the following functions are carried out:
- With the help of the mucous membrane and hairs, it cleans the air entering the nasal passages when inhaled.
- Cold air, getting into the sinuses, warms up.
- The nose acts as a resonator, so that each person has his own voice.
- The mucous membrane of the nasal cavity contains olfactory cells, so that a person has the opportunity to distinguish odors.
Each part of the nose is responsible for some specific work of the organ, but the complex structure of the bone-cartilaginous tissue contributes to a better treatment of air entering the lungs of the person through the sinuses.
Ethmoid sinuses
The ethmoid sinuses of the skull are located in the ethmoid bone. Each of the ethmoid sinuses takes its place between the sphenoid and frontal sinuses. The number of ethmoid sinuses varies from 5 to 10 on each side.
Before surgery on the cranial box, a thorough examination is required, since due to its anatomical features, the ethmoid sinuses are located in the immediate vicinity of the cranial fossa, as a result of which, when opening the cavity, the instrument can touch the soft tissues under the skull.
Frontal sinus
The frontal sinuses of the skull are located in the frontal bone. The structure of these sinuses is formed by four walls. The length of the special channel with which the frontal sinuses communicate with the middle nasal passage is 10 to 15 millimeters. The frontal sinuses are much smaller than the maxillary sinuses - from 4 to 5 cm³. It is very rare, but not excluded, that the frontal sinuses in a person may be completely absent.
Paranasal sinuses
Opinions about what the functions of the paranasal sinuses actually are, differ to this day. However, among the most common theories there is an opinion that these sinuses reduce the mass of the skull bone, without reducing its volume.
The paranasal sinuses of the human skull are a kind of shockproof buffer for injuries, and also play a direct role in enhancing voice resonance. Thanks to the paranasal sinuses, hypersensitive structures such as tooth roots and eyeballs are protected from hypothermia and overheating. This happens because in the sinuses of the nose, the air flow slows down a bit.
Sphenoid sinuses
The sphenoid sinuses of the skull are the most basic among all the others, and they are located in the sphenoid bone. Each of the sphenoid sinuses is formed by six walls. The bottom of the sinus is adjacent directly to the nasal concha, that is, it is a kind of roof for the nasopharynx. In the lower part of the main sphenoid sinus there is a hole that communicates with the nasal passage, which allows not to accumulate, but to completely withdraw the mucus that appears in the sinuses.
The sphenoid sinus begins to develop in children from 5 years. Moreover, in 7-10% of the adult population, the sphenoid sinus is absent.
Maxillary sinus
The maxillary sinuses of the skull are the largest among all existing. The internal part of the maxillary, or maxillary, sinuses is covered with ciliated epithelium, which contributes to the movement of the secreted mucus to the opening, which leads to the middle nasal passage. This sinus is formed using five walls, the sinus volume on each side is approximately 15-17 cm³.
One of the important anatomical features of the maxillary sinuses is a small fossa on the outside of the front wall. The localization of such a fossa is individual for each person: so, if the fossa is located too deep, then the sinus walls will be in close proximity to each other. It is also important to note that just above the maxillary sinuses is the infraorbital nerve.
Possible pathologies of the nasal sinuses
One of the main pathological manifestations that affect the paranasal sinuses of the skull is the inflammatory process. Such inflammations in most cases are bactericidal or infectious in nature and are called sinusitis. At the site of the focus of localization, the disease can be divided into several main forms:
- Frontitis - pathology affects the frontal sinuses.
- Sinusitis - defeat of the maxillary sinuses.
- Sphenoiditis - the sphenoid sinus is affected.
- Ethmoiditis - ethmoid sinuses are affected.
Rarely, malignant and benign tumors of the paranasal sinuses are found. In this regard, any treatment for sinusitis involves a very thorough examination, especially if the disease proceeds in a neglected form. In this case, the doctor prescribes to the patient such diagnostic methods as:
- Roentgenogram. This examination is preferably carried out in two projections - lateral and direct. A photo of the sinuses of a human skull with blackouts in the image will help to identify the exact location and size of the inflammatory process.
- Ultrasound examination - helps to establish the contours and boundaries of the focus of inflammation.
- MRI or CT scan of the sinuses. These analyzes help to refute or confirm suspicions of the development of an oncological process in the paranasal sinuses of the skull.
- An endoscopic examination, like CT of the sinuses of the nose, is prescribed for suspected development of a benign or malignant tumor.
If, according to the results of the tests, a severe lesion of any sinus is revealed, then the doctor can conduct a number of additional tests and send the samples for a biopsy.
The paranasal sinuses of the skull are very vulnerable and quite often undergo inflammatory processes, therefore, in order to avoid any serious complications at the first manifestations of the disease, you should immediately contact a specialist and start treatment.