SPLANCHO 2 EAR Flashcards
What nerve innervate all ear muscles?
CN III also called Facial nerve.
What are the extrinsic and intrinsic muscles of the ear?
EX: Auricolaris anterior, superior and posterior.
IN: Helicis major, Helicis minor, Tragicus and Antitragicus.
What is the Acoustic meatus?
It is the auditory canal which brings acoustic waves from the pinna to the eardrum. It is S shapes on the trans cranial plane. The external 2/3 has a cartilaginous skeleton while the inner 1/3 has a bony skeleton.
What is the Tympanic membrane?
The tympanic membrane, is the thin semitransparent membrane which separates the external from the middle ear. It is trilaminar, oval, it is 0.1 mm thick, and it is about 8 – 10 mm in diameter. It is positioned obliquely at an acute angle of around 55°. It has two parts called Pars Tensa, which is 80% and is semitransparent, and Pars Flaccida which is more opaque.
What is the blood supply of the tympanic membrane?
Outer surface is supplied by the Deep Auricular Artery.
The inner surface is supplies by the Anterior Tympanic Artery and the Posterior Tympanic Artery.
How is the tympanic membrane innervate?
The anterior and posterior part of the lateral surface are innervate by the Auricular Temporal nerve and the Auricular branch of the Vagus nerve respectively.
The medial surface is innervate by the Tympanic Branch of the Glossopharyngeal nerve.
What is the middle ear?
The middle ear consists of a cavity called tympanic cavity, which is separated from the external ear by the tympanic membrane and contains three ossicles: malleus, incus and stapes. These ossicles are connected to each other by means of muscles and ligaments. The tympanic cavity communicates anteriorly with the rhinopharynx by means of the Eustachian tube and posteriorly with a pneumatic cavity called mastoid cavity.
What are the middle ear ossicles?
The auditory ossicles are a series of small bones that connects the tympanic cavity to the oval window. They are the Malleus/Hammer, the Incus/Anvil, the Stapes/Stirrup. Their function is to amplify the sound pressure hitting the eardrum and transmit it to the inner ear.
What are the two functions of the middle ear?
To convert mechanical signals into electrical signals and to maintain balance by detecting position and motion aka vestibular function.
How long is the External Acoustic Meatus?
25mm.
What are ceruminous glands?
The skin in the lateral part of the emeritus contains these glands that from cerumen aka ear wax.
What are the two muscles that attach to the ossicles?
Tensor tympani and it inserts in the malleus. The strapedius muscle, it inserts on the stapes.
What is the Eustachian tube?
It is a narrow flattened channel approx 3.5 cm long, it is lined with pseudo stratified columnar ep. it contains goblet cells.
What are the components of the bony labyrinth?
Semicircular canals, vestibule and cochlea.
What is the vestibule?
It is a small oval chamber located in the center of the bony labyrinth. It contains the Utricle and the Saccule.
