Vocab List 3

Question 1

ossicles

Answer 1

• the malleus, incus and stapes
• 3 tiny bones that occupy most of the middle ear cavity
• reach adult size during fetal life
• 2 main purposes
• • to deliver sound vibrations to the inner ear fluid
• • to help inner ear from being overdriven by excessively strong vibrations

Question 2

malleus (hammer)

Answer 2

• most lateral of ossicles
• attached to connective tissue fibers of the TM attachment most intimate at middle of membrane and less so toward superior border
• attachment coupled with position of malleus in the middle ear cavity causes the membrane to be pulled inward to take shape of the cone
• consists of head, neck and 3 processes (manubrium, anterior and lateral process)

Question 3

manubrium (of the malleus)

Answer 3

• 1 of 3 processes of malleus
• firmly attaches to the TM by network of connective tissue of middle layer, and by mucous membrane
• this attachment causes the pull of the TM into a cone shape

Question 4

neck (of malleus)

Answer 4

• constriction of the malleus between the manubrium and the head
• point of attachment for lateral malleolar ligament

Question 5

anterior process (of malleus)

Answer 5

• spine like structure at the junction of the manubrium and the neck
• point of attachment for the anterior malleolar ligament

Question 6

head/capitulum (of malleus)

Answer 6

• bulbous and upward projecting portion of the malleus that occupies about half of the epitympanic recess
• posterior surface includes an articular facet for attachment of incus
• consists of an upper and lower portion due to a constriction in the center of the head

Question 7

incus (anvil)

Answer 7

• second of the linear ossicles
• named incus because resemblance to an anvil, actually looks more like a premolar tooth with two diverging roots
• consists of a body and two legs (crura) or processes

Question 8

body (of incus)

Answer 8

• anterior surface of the body has an articular facet, here is where it is joined with articular facet of the malleus
• body has two processes that arise from it at nearly right angles to each other; the short process (about 5mm long) and the long process (about 7mm long)
• long process contains a medially bent end with rounded projection called lenticular process

Question 9

lenticular process (of incus)

Answer 9

• projection of the long process which is tipped with cartilage and articulates with the head of the stapes
• appears almost as small as sesamoid bone

Question 10

stapes (stirrup)

Answer 10

• third of the linear ossicles
• named because of its resemblance to a riding stirrup
• consists of a head, neck, two crura & a footplate

Question 11

head (of stapes)

Answer 11

• presents a concave articular facet for reception of the lenticular process of the incus
• usually presents a small spine which indicates the attachment of the tendon of the stapedius muscle

Question 12

crura (of stapes)

Answer 12

• 2 crura of the stapes: anterior and posterior
• 2 delicate but incredibly strong struts that originate from points nearer the inferior rather than superior margin of the footplate
• crura are “channeled” on the inner surfaces which significantly reduces the mass of the stapes

Question 13

footplate (of stapes)

Answer 13

• partly osseous and partly cartilaginous
• occupies the oval window
• connected to the neck of the stapes by the anterior and posterior crura

Question 14

ligaments and articulations of the ossicles

Answer 14

• principal ligaments responsible for the suspension of the ossicular chain within the tympanic cavity
• 8 in total, including the tendons of the two middle ear muscles - these muscles are referred to as ligaments

Question 15

incudomallear articulation

Answer 15

• the saddle synovial joint between the incus and the malleus

Question 16

incudostapedial articulation

Answer 16

• synonym for incudostapedial joint
• the synovial joint between lenticular process of the long crus of the incus and the head of the stapes
• joint allows incus and stapes to move and articulate together, typically referred to as a “ball and socket” joint

Question 17

anterior malleal ligament

Answer 17

• fibrous band that extends from neck of malleus just above its anterior process to the anterior wall of the tympanic cavity close to the petrotympanic fissure
• some of the fibers also pass through the fissure to the spine of the sphenoid bone

Question 18

posterior incudal ligament

Answer 18

• one of the three ligaments that hold the incus in place, however, it secures the short process of the incus into the posterior incudal recess

Question 19

middle ear (tympanic) cavity

Answer 19

• space located between the TM and inner ear that houses the three auditory ossicles (incus, malleus, stapes) which convey vibrations through the oval window to the cochlea
• this is an air filled cavity that is also connected to the nasopharynx via the eustachian tube
• the middle ear conducts vibrations into mechanical energy by articulation of the ossicles in accordance with TM * mechanical energy into hydroelectric energy by pressing the footplate of the stapes into the oval window causing the endolymph in cochlea to move

Question 20

epitymanic recess

Answer 20

• the area of the tympanic cavity cranial to the TM
• contains the upper half of the malleus and greater part of the incus
• aka “attic”

Question 21

hypo-tympanum

Answer 21

• lower part of the middle ear cavity, in the temporal bone

Question 22

chorda tympani

Answer 22

• branch of the facial nerve that carries taste from the anterior 2/3 of the tongue and parasympathetic innervation to all salivary glands bellow the level of the oral fissure
• ultimately joins the lingual branch of trigeminal nerve

Question 23

tegmen tympani

Answer 23

• thin layer of bone that forms the roof of the tympanic cavity, separating it from the cranial cavity and the meningeal coverings of the brain

Question 24

tympanic air cells

Answer 24

• spaces in the tympanic cavity between the bony projections of the floor or jugular wall that sometimes communicate with the tubal air cells

Question 25

mastoid wall

Answer 25

• aka posterior wall
• wider above than below
• presents for examination the entrance tot he tympanic Antrum, the pyramidal eminence and the fossa incudis

Question 26

tympanic air cells of the mastoid wall

Answer 26

• spaces in the tympanic cavity between the bony projections of the floor or jugular wall that sometimes communicate with the tubal air cells

Question 27

pyramidal eminence (of mastoid wall)

Answer 27

• hollow and contains the stapedius muscle
• apex has very small orifice that is innervated by tendons of the stapedius
• located behind the oval window hear the prominence of the facial canal

Question 28

foramen of chorda tympani (of mastoid wall)

Answer 28

• small aperture through which courses the chorda tympani nerve
• located at the angle of the junction of the posterior (mastoid) and lateral membranous walls of the tympanic cavity
• behind the TM and on level with the process of the malleus

Question 29

incudal fossa (of mastoid wall)

Answer 29

• small depression in the lower and back part of the epitympanic recess which accommodates the short process of the incus ossicle

Question 30

aditus (of the mastoid wall)

Answer 30

• connecting link between the tympanic cavity and the tympanic Antrum
• entrance to the tympanic Antrum
• it is an oriface on the posterior wall of the epitympanic recess

Question 31

tympani antrum (of mastoid wall)

Answer 31

• communicates with mastoid air cells which provides indirect communication between the middle ear cavity and the mastoid air cells
• mucus membrane that lines middle ear cavity is continuous with that which lines the antrum

Question 32

carotid wall

Answer 32

• anterior carotid wall is wider at the top than at the bottom
• seperated from carotid canal by a thin plate of bone
• upper portion is perforated by the tendon of the tensor tympani and by the orifice of the eustachian tube