What Are the Ethmoid Sinuses?

It is located inside the ethmoid labyrinth above the nasal cavity. It is composed of gas-containing chambers with different degrees of vaporization. There are 3-18 small air chambers on each side. The size, arrangement and extension of the air chambers are extremely irregular, and the sides are extremely irregular. symmetry. The ethmoid sinus chambers vary widely, but all develop to varying degrees. The well-developed ethmoid sinus can be extended into the bottom of the frontal sinus, above or lateral to the sphenoid sinus, above the maxillary sinus, and frontal orbital, etc. In some cases, it can also reach the contralateral nasal cavity through the nasal septum or extend into the crown .

It is located inside the ethmoid labyrinth above the nasal cavity. It is composed of gas-containing chambers with different degrees of vaporization. There are 3-18 small air chambers on each side. The size, arrangement and extension of the air chambers are extremely irregular, and the sides are extremely irregular. symmetry. The ethmoid sinus chambers vary widely, but all develop to varying degrees. The well-developed ethmoid sinus can be extended into the bottom of the frontal sinus, above or lateral to the sphenoid sinus, above the maxillary sinus, and frontal orbital, etc. In some cases, it can also reach the contralateral nasal cavity through the nasal septum or extend into the crown. .

Chinese name

Ethmoid sinus

Foreign name

ethmoid sinus

Human body parts

Outside the nasal cavity above the ethmoid labyrinth

Constitute

Gas-containing small rooms with different levels of gasification

Form

Conical, pointed at the front and bottom in front of the sphenoid sinus

Overview of the ethmoid sinus :

1. The ethmoid sinus is located between the upper part of the outer wall of the nasal cavity and the inner wall of the orbit. It is a group of small rooms mainly located in the ethmoid labyrinth. It can be divided into three groups: anterior, middle, and posterior. The sieve funnel and vesicles of the nasal passage; the posterior chambers open in the upper nasal passage.

2. Ethmoidalsinus is located inside the orbit, inside the ethmoid labyrinth above the nasal cavity, and consists of the ethmoid, sacrum, sphenoid, maxilla and lacrimal bone. Above the ethmoid sinus is the meninges and frontal gyrus of the anterior cranial fossa, forefront is the frontal sinus, rear is the sphenoid sinus, below is the nasal cavity, and outside is the orbit. There are 8 to 18 small air cells in the ethmoid sinus. The size, arrangement and range of air cells are very irregular, the left and right sides are asymmetric, and the variation among individuals is large. It can be divided into three groups, anterior, middle and posterior, which are not connected to each other. The ethmoid sinus of the anterior group is opened in the middle nasal passage, and the ethmoid sinus of the posterior group is opened in the upper nasal passage. If the ethmoid sinus opening is blocked and a ethmoid sinus mucinous cyst is formed, the cyst can often invade the orbit through a very thin ethmoid paper template, causing the eyeball to protrude to the temporal side (Figure 8-18). The entire ethmoid sinus and the orbit are separated by a very thin bone plate, especially the thinnest cardboard. When the orbit is broken, it is easy to burst here, so that the content of the orbit and the hernia enter the ethmoid sinus. Ethmoid sinus infection is also prone to the orbit. The etiology of retrobulbar optic neuritis is also related to the inflammation of the ethmoid sinus in the posterior group and the proximity of the optic nerve. At the time of sinus surgery, the ethmoid sinus inflammation in the group should be protected to protect the optic nerve.

The boundaries and adjacent structures of the ethmoid sinus

1. The upper boundary is the bottom of the anterior cranial fossa, and it is inclined downward at an angle of 15 ° from front to back. The outer side of the ethmoidal roof is the outer side of the frontal orbital plate, and the inner side is connected to the sieve plate. There are two ways to connect the sieve roof and the sieve plate: platform type: the inner and outer sides of the sieve roof are almost at the same level as the sieve plate; high table: the position of the sieve plate is lower and forms a steep straight with the inside of the sieve plate This height difference forms a depression at the top of the sieve called a sieve depression. The inner wall of the sieve depression is extremely thin, which can easily lead to anterior skull base injury and cerebrospinal fluid nasal leakage during surgery. Xu Geng had observed the connection of the sieve roof and the sieve plate of 100 skulls, and found that 56 cases were high on both sides, 32 cases were horizontal, and 12 cases were horizontal on one side and High desktop. It can be seen that high benchtops are more common and should be highly valued by the surgeon. The sinus coronary CT before surgery can provide important information. When the anterior ethmoid artery enters the ethmoid sinus from the orbit, walking in the bone canal level or slightly below the apical level is an important sign to determine the apical level.

2.Outer bound

That is, the inner wall of the orbit is composed of lacrimal bone and paper template. The latter occupies most of the outer wall of the ethmoid sinus. It is thin and can also have congenital defects or fissures. At the level of the ethmoid, the anterior and posterior ethmoidal arteries enter the ethmoid sinus through this, and the paper template is in the same sagittal position as the medial wall of the maxillary sinus. Once the operation is damaged, intraorbital complications are likely to occur.

3, inside boundary

It is the structure of the outer wall of the nasal cavity, and the middle turbinate and attachment are the signs of this boundary.

4. Frontier

It consists of a frontal ethmoidal notch, a nasal condyle, and a maxillary frontal process. The important structure at this site is the frontal recess, which is the frontal sinus opening.

5.Back bound

The anterior wall of the sphenoid sinus. But sometimes it depends on the development of the ethmoid chamber in the last group. The ethmoid chamber in the posterior group may extend to the outside and above the sphenoid sinus, forming the sphenoid or upper sphenoid ethmoid, even beyond the posterior boundary of the sphenoid sinus. The world is actually the front wall of the saddle. If the sieving is too deep during the operation (before reaching the anterior wall of the sphenoid sinus more than 8,0 cm deep from the front nostril), this situation should be considered.

6, lower bound

That is, the structure of the outer side wall of the middle nasal passage, such as ethmoid bubble, hook process, sieve funnel, etc.