There is also a building in our ears.Small house
We have seen all kinds of houses in life. Actually, you know, there is also a in our ears.“Small house”, its structure is so powerful that it is enough to surprise you, that is the tympanum.Do you say that there is an amazing thing in the ear?“Small house”!
The tympanic chamber is a gas-filled cavity, shaped like a hexahedral box, like a small room. Divided into upper, lower, inner, outer, front and rear six walls, located between the tympanic membrane and the lateral wall of the inner ear, forward to the nasopharynx through the eustachian tube; backward to the sinus entrance and sinus sinus, mastoid gas The room is connected.
1. Drum outdoor wall
It consists of a bone and a membrane. The smaller part of the bone, that is, the outer wall of the upper tympanic cavity, is located above the level of the upper wall of the bony external auditory canal and is composed of the outer plate of the sacral scale. The membrane is the tympanic membrane, which is between the tympanic cavity and the external auditory canal and is the main component of the outer wall of the drum.
The tympanic membrane is an elliptical semi-permeable membrane that is inwardly recessed.9mm, about 8mm wide, about 0,1mm thick, slightly thicker, and a fibrous cartilage ring formed around the middle layer of the tension is embedded in the sulcus, called the tension. The tympanic membrane at the drum incision is directly attached to the scale, which is relatively slack and is called the slack. The tympanic membrane is shaped like a speaker, tilted forward, outward, and downward, and has an 45°-50° angle with the base of the external auditory canal; in neonates, it is approximately 35°.The central point of the tympanic membrane corresponds to the tip of the hammer stem, called the umbilicus. From here on, slightly forward to the upper edge of the tension, there is a small gray-white protrusion called a hammer. Between the umbilicus and the hammer convex, there is a white stripe called a hammer pattern. The anterior and posterior malleolus of the hammer bone are formed by the short protrusion of the hammer bone, which is the boundary line between the tension portion and the slack portion of the tympanic membrane. When the otoscope is examined, there is a triangular reflection area in front of the tympanic membrane, which is called a light cone. Therefore, when the tympanic membrane is invaded, the light cone can disappear or be deformed.
2. Upper wall of the tympanum
That is, the tympanic lid or the sky cover. thick3-4mm is also thin as paper. The tympanic cavity is separated from the cranial fossa by this wall.
3. Lower wall of the tympanum
Also known as the jugular vein wall, the tympanic and jugular bulbs are separated by a thin, thin plate that is smaller than the upper wall. If there is a defect in this wall, the blue color of the jugular bulb can be faintly visible through the lower part of the tympanic membrane.
4. Drum wall
Also known as the labyrinth wall, the outer wall of the inner ear. The drumstick is a large protrusion in the center of the inner wall, which is the base of the cochlea, and has a tympanic plexus on the surface. The vestibular window or the oval window is oval in shape and approximately3mm2. It is located in the small recess above the drumstick and opens inward to the vestibule of the inner ear, which is closed by the humerus (foot plate) and the surrounding ligaments around it. The snail window or round window is round and located in the small recess in the lower back of the drum. It is closed by a round window membrane. This membrane is also called the second tympanic membrane. The area is about 2mm2. unit.A facial nerve tube or a facial nerve sac, located above the vestibular window. The horizontal part of the facial nerve is inside the tube, and reaches the inner side and the bottom of the entrance of the sinus sinus along the posterior direction of the oval window, and is turned down into the posterior wall of the external auditory canal. This section is called the vertical part of the facial nerve or the mastoid part, and the posterior nerve is the stem of the stalk. . The outer semicircular canal or the outer semicircular canal is located at the posterior upper part of the facial nerve canal, which is a good site for the lost fistula. The spatula is located slightly above the front vestibular window and is formed by bending the tympanic end of the musculoskeletal tube. The tendon of the tympanic membrane muscles bypasses the spatula and flexes outward at a right angle to the inside of the upper part of the hammer stem.
5. Back wall of the tympanum
That is, the mastoid wall is wide and narrow. The vertical part of the facial nerve passes through the inside of this wall. The upper part of the posterior wall has a sinus entrance The tympanic cavity is connected to the tympanic cavity and the mastoid gas chamber by the entrance of the sinus. The inner side of the posterior wall, corresponding to the height of the vestibular window, has a small conical protrusion, called the hammer cone bulge, and the tendon muscle is attached to the back of the humerus neck. The rear wall and the outer wall intersect, and the inner side of the upper end of the sulcus has a tympanic cavity of the tympanic tubule from which the tympanic cord is separated from the facial nerve into the tympanic cavity.
Under the cone bulge, the inner side of the vertical tube of the facial nerve has a crypt containing a gas chamber called a tympanic sinus or a cone crypt. On the upper rear side of the cone ridge, behind the anvil’s socket, there is a crypt containing a gas chamber called a facial recess. The bottom is slightly concave at the tip of the concave triangle, the bottom edge of which is the anvil socket, the inner side is the vertical part of the facial nerve, and the outer side is the tympanic nerve.
6. Front wall of the tympanum
That is, the arterial wall. The lower part is separated from the internal carotid artery by a very thin bone plate. Upper part2 mouth, the lower part is the tympanic cavity of the eustachian tube half tube, the upper part is the opening of the tympanic membrane half tube, and the two half tubes are called the muscle eustachian tube.
Do you know that there is an amazing thing in the ear?“Small house”!
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