The middle ear (auris media), which is also called the tympanic cavity (cavum tympani), a conductive system, which includes several components.
The tympanic membrane (membrana tympani) is located on the border of the outer and middle ear is the outer wall of the tympanum. Its task is the perception of sound waves and air their further transfer of the middle ear. The tympanic membrane is a connective tissue of the external ear covered with leather, and from the middle ear - the mucous membrane. In the center of the tympanic membrane is observed funnel-shaped bend in the direction of the middle ear. Convex side funnel is attached to the handle of a hammer to form the navel of the eardrum (umbo membranae tympani).
The tympanic cavity (cavum tympani) is located near the temporal bone. Its inner surface is covered with mucous membrane and the inner wall are two holes in the upper part - the foramen ovale, which is the threshold window (fenestra vestibuli), and the bottom - the round, which is a window of the cochlea (fenestra cochleae).
In the tympanum are the auditory ossicles (ossicula auditus), which are connected with each other joints and is a sound-conducting system of the middle ear. There are three pits, each of which is named according to their shape.
|In Fig. 288.
The eardrum and auditory ossicles
1 - hammer head;
2 - short leg anvil;
3 - foot long anvil;
4 - hammer handle;
5 - auditory tube;
6 - eardrum
Hammer (malleus) adjacent to the inner surface of the tympanic cavity, connecting to the eardrum handle of the malleus (manubrium mallei), a curved arm and hammer head (caput mallei), which is located in the upper part of the tympanic cavity, grow together with other bone - a hard place. The connection to the tympanic membrane is provided by ligaments. The head of the hammer and the hammer handle connects the malleus neck (collum mallei). Depart from the grip side arm (proceessus lateralis) and the anterior process (processus anterior). To it is attached tendon muscles that bend the ear drum (m. tensor tympani).
|In Fig. 289.
The auditory ossicles
1 - short leg anvil;
2 - the body of the anvil;
3 - hammer head;
4 - longest leg of the incus;
5 - anterior process of the malleus;
6 - hind foot stirrup;
7 - the hammer handle;
8 - footplate;
9 - front foot stirrup
Anvil (incus) consists of an anvil body (corpus incudis), which runs a short leg (crus breve) and the long leg (crus longum). The body of the incus ligament is attached to the upper wall of the tympanic cavity, the short leg - to the eardrum, and a long leg - the third bone, the stapes. The front surface of the body has a saddle shape of an anvil and hammer connected to the head.
Stirrup (stapes) is attached to the anvil covered with cartilage joint head of the stapes (caput stapedis), which has a funnel shape. From the front of the stapes head depart the front leg (crus anterius) and rear leg (crus posterius). At the base of the latter is attached tendon stapedius muscle (m. stapedius). The legs are connected to the head through the neck of the stapes (collum stapedis). The space between the legs of the stirrup filled membrane (membrana stapedis), and the end of the legs are attached to the footplate (basis stapedis). The upper edge of the base is slightly convex and the lower concave surface is covered with loose gravel. The base of the stapes through the connective tissue attached to the window arches of bone of the labyrinth.
The auditory tube (tuba auditiva) connects the tympanum to the upper division pharynx. Its length is 3.5-4 cm, 2 / 3 of which are cartilage formation, and the third - the bone. From within the auditory tube is lined with mucous membrane, which contains the tube cancer (glandulae tubariae), and lymph nodules.
a., aa. — arteria, arteriae (artery, the artery)
lig., ligg. — ligamentum, ligamenta (ligament, the ligaments)
m., mm. — musculus, musculi (muscle, the muscle)
n., nn. — nervus, nervi (nerve, the nerve)
r., rr. — ramus, rami (branch)
s. — seu (or)
v., vv. — vena, venae (vienna)