The ear, also known as the vestibular cochlea, is divided into:Outer ear, middle ear, inner ear
1) Auricle: cartilage as a scaffold, outer coat**.
2) External auditory canal: It is in the shape of "S", and when the external auditory canal is examined, the auricle needs to be stretched outward and upward.
3) Tympanic membrane: located between the external auditory canal and the middle ear, it is oval, translucent, and inclined outward and downward. The upper part is the relaxation part, the lower part is the tension part, ** inwardly concave is the tympanic umbilicus, and there is a triangular light cone in the anterior inferior.
1) Tympanum: The tympanic cavity is located in the temporal bone, between the tympanic membrane and the inner ear, and contains the ossicles.
1 Six walls of the tympanum.
1) Upper wall: It is the tympanic cover, which is adjacent to the cranial fossa through a thin bone plate.
2) Inferior wall: It is the wall of the jugular vein, with a thin bone plate separating it from the internal jugular vein.
3) Anterior wall: It is the wall of the carotid artery with an opening of the Eustachian tube in the anterior inferior.
4) Posterior wall: it is the mastoid wall, which leads to the mastoid chamber.
5) Lateral wall: It is the wall of the eardrum, which is separated from the outer ear through the eardrum.
6) Inner side wall: It is a labyrinth wall, with vestibular windows and worm windows.
2 Ossicles: 3 on each side, 6 in total. They are malleus, incus, and stapes.
The connection method is: tympanic membrane - malleus - incus - stapes - vestibular window.
b) Eustachian tubes.
The anterior Eustachian tube communicates with the nasopharynx and the tympanic cavity posteriorly. The eustachian tube in children is short, flat and straight, and upper respiratory tract infection can easily spread to the middle ear through the eustachian tube, causing otitis media.
The inner ear is located within the petrous part of the temporal bone and is called a labyrinth. These include bony labyrinth and membranous labyrinth. The bone labyrinth contains perilymph, and the membranous labyrinth contains endolymph. The internal and external lymph do not communicate with each other.
(1) Bone labyrinth: It is divided into bony vestibule, bony semicircular canal, and cochlea.
1 Bony semicircular canal: three semi-annular tubules perpendicular to each other.
2 Bony vestibule: between the semicircular canal and the cochlea, with vestibular and cochlear windows on the lateral wall.
3 Cochlea: Shaped like a snail shell, it consists of a spiral tube around the snail axis.
(2) Membrane labyrinth: It is divided into membranous semicircular canals, utricles and balloons, and cochlea.
1 Membranous semicircular canal: located in the bony semicircular canal, it is also divided into three, the bulging part is called the ampulla of the membrane, and there is an ampullary crest in it which is a positional receptor.
2 Utricle and balloon: located in the vestibule, two membranous sacs that communicate with each other. There are utricle and balloon plaques inside, which are also positional receptors.
3 Worms. It is a membranous tube located in the cochlea, with a triangular cross-section, the upper wall is the vestibular membrane, the lower wall is the basement membrane, and the basement membrane has spirals, which are auditory receptors.