Hi. This is Peter from AnatomyZone and in this tutorial we're going to be taking a look at the
anatomy of the external ear…So the external ear consists of two parts.
The outer part the auricle also known as the pinna projects from the side of the head.
And then we have the external auditory meatus or external acoustic canal, which leads to the
middle ear…So let's take a look at the auricle first.
The auricle is a cartilaginous structure covered by skin.
Which projects from the side of the head and is involved in capturing sound
…It consists of the following parts.
This outer bit here is the helix, this curved outer rim…And then just anterior to the
helix we have the antihelix.
There are two crura or limbs which form this Y shape with a superior crus and the inferior crus
…The lobule is this fleshy non
cartilaginous part, which forms the inferior part of the auricle.
And this is what's known as your ear lobe…The concha is found at the center of the auricle.
And the external auditory meatus forms medially from here…This here is the tragus, which is
seen anterior to the external auditory meatus.
And then on the opposite side we have the anti-tragus.
Superior to the fleshy labia…In terms of the muscles of the external ear.
You've got both intrinsic and extrinsic muscles associated with the auricle.
The intrinsic muscles run through the cartilaginous framework of the auricle itself.
Whereas the extrinsic muscles consist of three auricular muscles.
You've got the anterior, the superior and the posterior auricular muscles…There are
several nerves which provide sensory innervation to the auricle
…The deep parts of the auricle are supplied by branches of the facial nerve.
Cranial nerve number seven. As well as the vagus nerve number 10…The superficial or more
peripheral parts of the auricle is supplied by the greater auricular and the lesser occipital nerves.
And these arise from the cervical plexus. And you've also got innervation provided by the
auriculotemoral branch of the mandibular nerve.
The third branch of the trigeminal nerve…The arterial supply to the auricle from branches of
the external carotid artery…The posterior auricular artery.
The superficial temporal artery and the occipital artery
…The external auditory meatus lies deep to the concha.
And extends medially to the tympanic membrane. Which is also known as the
eardrum…It takes an S shaped course.
It's not entirely straight. So during otoscopic examination the auricle is pulled up and
backwards to straighten it out…The lateral third of the external auditory meatus is cartilaginous.
whereas the medial two-thirds are boney formed by the temporal bone…It's lined by skin along
its course and contains small hair cells and specialized sweat glands, which produce cerumen…
Also known as ear wax…In terms of the sensory innervation to the external auditory
meatus it receives branches from the auriculotemporal nerve and the auricular branch of the vagus nerve
…The tympanic membrane is a thin membrane which separates the external ear from the middle ear
compartment…It transmits sounds received by the external auditory meatus to the ossicles of
the middle ear via the oval window and into the cochlea…
It's attached to the temporal bone by peripheral fibrocartilaginous ring.
And it's angulated medially from superior to inferior and from posterior to anterior.
So we're now taking a look at the tympanic membrane here.
And if you just imagine looking directly into the ear canal as you would do during otoscopy,
this is what the diagram is showing here…Anterior is on the right of the diagram and posterior
on the left of the diagram…This point here is the umbo, which is a concavity where they
handle or manubrium of the malleus attaches…I've returned to the 3d model coronal section just
to show you the relationship of the malleus to the tympanic membrane as you saw in the diagram…
you can see here the lateral process of the malleus superiorly and the handle of the malleus or
manubrium extending inferiorly along the inner surface of the tympanic membrane.
With its tip at the umbo…Just superior to umbo and slightly anterior we have the lateral
process of the malleus…And then extending anteriorly and posteriorly from the lateral process
, we have the anterior and posterior malleolar fold respectively.
You can see here this small triangular area just above the malleolar folds.
This is an area where the tympanic membrane is a little bit thinner and looser.
And it's known as the pars flaccida The rest of the tympanic membrane is thicker and tighter,
and it's known as the pars tensa This small area
here just seen anteroinferior to umbo is known as the cone of light.
And this is where we get a reflection of light on otoscopy…In terms of innervation the outer
surface of the tympanic membrane is innervated by the fifth seventh and 10th nerves.
So the trigeminal facial and vagus nerves. And the inner surface is innervated by the ninth
nerve The glossopharyngeal nerve…So that's the anatomy of the external ear.
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in the video description for an interactive 3d model of the anatomy that
you've seen today…Thanks for watching…