Section 2 Flashcards
Another name for the Auricle
pinna
Temporal Bone
The portion of the cranium that houses a portion of the external ear; as well as the middle ear, inner ear and includes the cochlea and vestibular apparatus and the 7th and 8th nerves.
External Auditory meatus
also called the auditory canal. Located anterior to the mastoid process of the temporal bone.
HOw many bones does each temporal bone articulate with?
5 occipital bone parietal bone sphenoid bone zygomatic bone The mandible
What portions make up the temporal bone?
Squamous
Mastoid
Petrous
Tympanic
Squamous Portion of Temporal Bone
thin and translucent. forms anterior and upper portion of the bone.
Fan shaped, contains mandibular fossa (place of articulation for the condylar process of the mandible). SUPERIOR to the EAM.
Zygomatic Process
The arched process that articulates with the zygomatic bone. Pretty sure its part of the squamous portion.
Mandibular fossa
a shallow depression that articulates with the mandibular condylar process. located on squamous portion.
Tympanic portion
The portion that surrounds the external auditory meatus(EAM).
EAM
external auditory meatus. the circular external opening into the auditory/ ear canal.
Styloid process
part of the tympanic portion. narrow projection of bone that angles downward and gives attachment to a ligament and 3 muscles.
Mastoid portion
Lies below squamous portion and behind the typanic portion. Contains the mastiod process.
Mastoid process
The large prominence located posteriorly to the EAM.
Petrous portion
Solid wedge of bone that forms most of the posterior and inferior portions of temporal bone. located medial to EAM. Houses the IAM that transmits the 8th nerve from the internal ear to the brain. Houses most of the ear.
petrous portion of the ear houses what three movable bones?
The three ossical bones
M, I ,S
Auricle
aka pinna. directs sound into the EAM.
Composed of elastic fibro-cartilage.
Helix
Ridged rim along the posterior and superior part of the pinna. Originates at the crus of the helix and terminates superior to the lobule.
Lobe/ Lobule
Devoid of cartilage, highly elastic, most inferior part of the pinna.
Tragus
The cartilaginous flap that partially covers the opening of the ear canal
Antihelix
A ridge located anterior to the scaphoid fossa. Essencially runs parallel to the helix In the upper portion it slips into two segments called the crura of the antihelix (Superior and inferior).
Cruz of the helix
origination point of the helix.superior to opening of the EAM. birdbeak
crura of antihelix
two anterior and superior elevations of the auricle located on the upper portion of the Antihelix and form two sides of the triangular fossa. Inferior crura forms the roof of the concha.
Concha
a deep depression of the auricle, divided into to portions. The cymba concha and cavum concha. both are Bordered by the antihelix, tragus and antitragus.
Cymba cochae
deep depression located between the inferior antihelix and cruz of the helix.
Cavum conchae
larger inferior portion of the conchea. kinda “c” shaped,flat portion of ear that touches the helix cruz and targus.
Intertragic notch/intertragalincisure
notch separating the targus and antitargus
scaphoid fossa/scapha
long narrow groove that runs in between the helix and the antihelix
antitragoinsisure
separates the tail of the helix and the antihelix (cartilage view)
Auricular muscles
Extrinsic- connect the auricle to the hear. vestigial- serve little or no function and innervated by fracial nerve 7. 3 muscles- superior, anterior and inferior.
Intrinsic- connct auricle parts together, makes small changes to the pinna, no real purpose other than holding the shape and innervated by facial nerve 7.
Ear canal/ EAM
About an inch long. Wider a the opening and then becomes more narrow. At the end of the EAM is the isthmus. The tube is not a perfect cylinder, but rather an elongated/lazy “s”. Runs roughly perpendicular to the head.
Structure of the EAM and slope
At either end the EMa slopes downward- this helps minimize the retention of water in the ear for adults. kids are more susceptible.
Near the opening the first 1/3 or 1/2 of the EMA is carlaginous and slightly malleable. the last 1/2 or so is boney as it passes through the temporal bone.
Boney portion of EAM is formed by three main structures….?
The tympanic portion of the temporal bone, squamous portion and the condoyal of the mandible.
Is there are osseous/boney portion to the EAM in humans at birth?
Nope! it develops over several years.
Ear canal is covered by an epidermal lining..
closely adheres to the supportive structures of the canal. covers the length of the and eventually forms the lateral most layer of the tympanic membrane and the medial (inside) portion of the EAM.
The outer lining contains hair cells and glands that secrete a waxy substance called cerumen.
Cerumen
Ear wax…Serves protective functions for the peripheral hearing system. Protects ear canal from drying out and has an acidic pH
Sebaceous glands
Contribute to production of cerumen. these cells are located close the the hair follicles. produce an oily substance that lubricates the ear canal. Made up of broken down cells.
Cerumenous glands
The cells that create the wax-like substance that mixes with the oily substance from the sebaceous glands. Eventually forming earwax.
Differences in cerumen…
Varies depending on the contribution of oily and waxy substance and varies by race as well.
Asian- more likely to have flakey
Caucasian, african american, latino- more likely to have wet and sticky.
ho does cerumen come out the the ear?
The outer layer of skin migrates out
Protective functions of cerumen
slightly antibacterial/anti-fungal. may repel or discourage insects from entering.
Isthmus
A constriction which marks the junctions of the cartilaginous and body framework of the EAM.