Ear Flashcards
Parts of the incus
Body of incus, long and short limbs
Parts of the malleus
Head of, neck of , anterior and lateral process, handle of malleus
Most medial bone of the osseus chain
Stapes
Largest ossicle
Malleus
Parts of the stapes
Head of, anterior and posterior limbs, base of stapes
What does the head if stapes articulate with
Long limb of incus
2 muscles associated with the ossicles
Stapedius and tensor tympani
Location of tensor tympani
Lies in bony canal above the pharyngotympanic tube, g w of shpenoid, own body canal and inserts into the handle of malleus
Innervation of tensor tympani
Branch from the mandibular nerve
Contraction of tensor tympani
Pulls handle of m medially and so tensing the tympanic membrane
Location if Stapedius
Inside the pyramidal eminence in mastoid wall
Innervation of Stapedius
Branch from the facial nerve
Contraction of Stapedius
Pulls stapes posteriorly and prevents excessive oscillation
Supply to middle ear
1) tympanic branch of the maxillary artery
2) mastoid branch from the occipital and posterior auricular arteries
3) middle meaning earl a,
4) artery of the pterygpid canal and
5) tympanic branch of the internal carotid artery
Venous drainage of middle ear
Pterygpid plexus of veins
Superior petrosal sinus
Innervation of middle ear
1) tympanic plexus by tympanic nerve from glossopharyngeal n and branches of the internal carotid plexus
Location of tympanic plexus
Promontory
Another name for the plexus of nerves surrounding the internal carotid artery
Catoticotympanic plexus
What does the tympanic plexus innervatate
Pharyngotympanic tube , mucous membranes of the middle ear, mastoid area
What major branch does the tympanic plexus give off
Lesser petrosal nerve into the preganglionic parasympathetic fibers to the otic ganglion (exits through foremen ovale)
Location of inner ear
In the petrous part of the temporal bone and between the labyrinthine wall and internal acoustic meatus
3 parts of the bony labyrinth
1) vestibule
2) semicircular canals
3) cochlea
Bony labyrinth lined by
Periosteum
B.L contains
Perilymph
6 parts of the membranous labyrinth
Cochlear DUCT
Lateral anterior and posterior semicircular DUCTS
Utricle
Saccule
Organs of balance
SC DUCTS
utricle
Saccule
Innervation of ML
Vestibulocochlear nerve and divides after entering the internal acoustic meatus
Central part of the bony labyrinth
Vestibule
Narrow canal leaving vestibule into the posterior surface of petrous part of temporal bone
Vestibular aqueduct
Dilated end of semicircular canals
Ampulla
Each canal is in ____ angles to the other two
Right
How many twists does the cochlea turn
2 1/2 or 2 3/4 times around the central column off bone
The central column of bone in cochlea
Modiolus
Thin lamina of bone entering laterally throughout the length of Modiolus
Lamina of Modiolus / spiral lamina
Attachéd to the lamina and held on central position circling around Modiolus
Cochlear duct
2 canals of the cochlear duct
1) scala vestibuli
2) scala tympani
Narrow slit where canals are continuous with each other in cochlea
Helicotrema
Scala tympani is continuous with
The secondary tympanic membrane covering round window
Small channel near round window that opens into the posterior cranial fossa and is a connection between peri lymph and subarachnoid space
Cochlear canaliculus
5 structures that form the vestibular apparatus (organ of balance )
Utricle, saccule and 3 SC DUCTS
Organ of hearing
Cochlear duct
Larger sac
Utricle
Oval,
Elongated and irregular in shape in post sup part of vestibule
Utricle
3 SC DUCTS empty into
Utricle
Smaller rounded sac lying in the antinf part vestibule of BL
Saccule
Cochlear duct empties into
Saccule
Connects utricle and saccule
Atriculosaccular duct
Branches from the atriculosaccular duct and enters vestibular aqueduct
Endolymphatic duct
Channel through the temporal bone
Vestibular aqueduct
An extradural pouch in the posterior aspect f the petrous part of the temporal bone
Endolymphatic sac
Sense organ of utricle and saccule
Macula of utricle and saccule
Sense organ in the ampulla of the SC Ducts
Crista
Utricle responds to
Centrifugal and vertical acceleration
Saccule responds to
Linear acceleration
Receptors in 3 SC ducts respond to
Movement in any direction
Central bony core of the cochlea
Modiolus
Shape of cochlear duct
Triangular
Outer wall against the bony cochlea consisting of thickened epithelial lined periosteum
Spiral ligament
Roof of the cochlear duct which separates endolymph in the cochlear duct from the peri lymph in the scala vestibuli
Vestibular surface membrane
Floor of the cochlear duct which separates endolymph from peri lymph in scala tympani which contains lamina and a ____ to the spiral ligament
Basilar membrane