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Questions and Answers
The cartilaginous portion of the external acoustic meatus is entirely circular in shape.
The cartilaginous portion of the external acoustic meatus is entirely circular in shape.
False (B)
Ceruminous glands, found in the cartilaginous part of the external acoustic meatus, are modified sebaceous glands that secrete earwax.
Ceruminous glands, found in the cartilaginous part of the external acoustic meatus, are modified sebaceous glands that secrete earwax.
False (B)
The external acoustic meatus is at its widest point at the isthmus, a few millimetres from the tympanic membrane.
The external acoustic meatus is at its widest point at the isthmus, a few millimetres from the tympanic membrane.
False (B)
The auricle and external meatus primarily receive their blood supply from the anterior auricular and superficial temporal arteries.
The auricle and external meatus primarily receive their blood supply from the anterior auricular and superficial temporal arteries.
Lymphatic drainage from the auricle and external meatus flows exclusively to the occipital lymph nodes.
Lymphatic drainage from the auricle and external meatus flows exclusively to the occipital lymph nodes.
The great auricular nerve supplies the lateral surface of the auricle, including both the upper and lower parts.
The great auricular nerve supplies the lateral surface of the auricle, including both the upper and lower parts.
The tympanic cavity is situated within the squamous bone.
The tympanic cavity is situated within the squamous bone.
The tympanic membrane is positioned at an angle of approximately $35°$ with the external acoustic meatus.
The tympanic membrane is positioned at an angle of approximately $35°$ with the external acoustic meatus.
The pars flaccida, or Shrapnell's membrane, is the main, tense part of the tympanic membrane.
The pars flaccida, or Shrapnell's membrane, is the main, tense part of the tympanic membrane.
The mucosal side of the tympanic membrane receives its blood supply from the deep auricular artery.
The mucosal side of the tympanic membrane receives its blood supply from the deep auricular artery.
The bony part of the auditory tube is supplied by branches from the tympanic plexus, which originates from the facial nerve.
The bony part of the auditory tube is supplied by branches from the tympanic plexus, which originates from the facial nerve.
Approximately 6 mm superior to the stylomastoid foramen, the chorda tympani exits the facial nerve within the facial canal.
Approximately 6 mm superior to the stylomastoid foramen, the chorda tympani exits the facial nerve within the facial canal.
A vertical section through the cartilage of the auditory tube reveals a shape resembling an inverted 'L', with the longer limb being anterior.
A vertical section through the cartilage of the auditory tube reveals a shape resembling an inverted 'L', with the longer limb being anterior.
The cilia within the respiratory mucous membrane lining the cartilaginous part of the auditory tube beat towards the nasopharynx.
The cilia within the respiratory mucous membrane lining the cartilaginous part of the auditory tube beat towards the nasopharynx.
The medial wall of the mastoid antrum is located 25 mm deep to the suprameatal triangle.
The medial wall of the mastoid antrum is located 25 mm deep to the suprameatal triangle.
The human external acoustic meatus's inner two-thirds consists of cartilage, while the outer third is bone.
The human external acoustic meatus's inner two-thirds consists of cartilage, while the outer third is bone.
The auditory tube connects the middle ear to the nasopharynx.
The auditory tube connects the middle ear to the nasopharynx.
While intrinsic ear muscles have a sphincter and dilator function in lower animals, they perform a similar function in humans.
While intrinsic ear muscles have a sphincter and dilator function in lower animals, they perform a similar function in humans.
The tympanic membrane is located at the medial end of the external acoustic meatus.
The tympanic membrane is located at the medial end of the external acoustic meatus.
The lobule of the ear contains the same resilient yellow elastic cartilage as the rest of the auricle.
The lobule of the ear contains the same resilient yellow elastic cartilage as the rest of the auricle.
The shape of the auricle is determined by the folds in the underlying yellow elastic cartilage.
The shape of the auricle is determined by the folds in the underlying yellow elastic cartilage.
Extrinsic ear muscles in humans serve to move the auricle, similar to their function in lower animals.
Extrinsic ear muscles in humans serve to move the auricle, similar to their function in lower animals.
The bony portion of the external acoustic meatus is formed by the squamous part of the temporal bone.
The bony portion of the external acoustic meatus is formed by the squamous part of the temporal bone.
The stapedius muscle emerges from the base of the pyramid and inserts into the front of the stapes' neck.
The stapedius muscle emerges from the base of the pyramid and inserts into the front of the stapes' neck.
The tensor tympani muscle has an antagonistic muscle that aids in restoring the equilibrium of the eardrum.
The tensor tympani muscle has an antagonistic muscle that aids in restoring the equilibrium of the eardrum.
The mucous membrane of the middle ear is solely supplied by the tympanic branch of the glossopharyngeal nerve.
The mucous membrane of the middle ear is solely supplied by the tympanic branch of the glossopharyngeal nerve.
The chorda tympani carries taste fibers from the posterior part of the tongue.
The chorda tympani carries taste fibers from the posterior part of the tongue.
The lesser petrosal nerve carries preganglionic parasympathetic fibers that synapse in the otic ganglion before innervating the parotid gland.
The lesser petrosal nerve carries preganglionic parasympathetic fibers that synapse in the otic ganglion before innervating the parotid gland.
The facial nerve's primary function in relation to the ear is directly within the middle ear cavity.
The facial nerve's primary function in relation to the ear is directly within the middle ear cavity.
The greater petrosal nerve emerges directly into the middle ear cavity.
The greater petrosal nerve emerges directly into the middle ear cavity.
Veins from the middle ear drain directly into the internal jugular vein.
Veins from the middle ear drain directly into the internal jugular vein.
Blood is only supplied to the middle ear from branches of the internal carotid artery.
Blood is only supplied to the middle ear from branches of the internal carotid artery.
The tympanic plexus solely provides sensory innervation to the middle ear.
The tympanic plexus solely provides sensory innervation to the middle ear.
The trochleariform process, a funnel-shaped projection, originates from the anterior end of the facial nerve canal.
The trochleariform process, a funnel-shaped projection, originates from the anterior end of the facial nerve canal.
The tegmen tympani, a laminar projection of petrous bone, roofs the canal for the tensor tympani, the tympanic antrum, and houses the temporal lobe within the middle cranial fossa.
The tegmen tympani, a laminar projection of petrous bone, roofs the canal for the tensor tympani, the tympanic antrum, and houses the temporal lobe within the middle cranial fossa.
The internal opening of the tympanic canaliculus, through which the tympanic branch of the glossopharyngeal nerve enters, is located at the anterior wall's posterior end.
The internal opening of the tympanic canaliculus, through which the tympanic branch of the glossopharyngeal nerve enters, is located at the anterior wall's posterior end.
The posterior wall of the tympanum features the aditus, an aperture leading into the tympanic antrum, above which lies the ridge of the facial nerve canal and the bulging of the stapedius muscle.
The posterior wall of the tympanum features the aditus, an aperture leading into the tympanic antrum, above which lies the ridge of the facial nerve canal and the bulging of the stapedius muscle.
The mallear folds are attached to the manubrium of the malleus, close to the tympanic membrane.
The mallear folds are attached to the manubrium of the malleus, close to the tympanic membrane.
The anterior process of the malleus, embedded within the anterior ligament, connects directly to the mandibular condyle via the sphenomandibular ligament.
The anterior process of the malleus, embedded within the anterior ligament, connects directly to the mandibular condyle via the sphenomandibular ligament.
The incus's short limb rests in a fossa on the posterior wall below the aditus, while the long limb, parallel to the stapes, terminates in the lenticular process.
The incus's short limb rests in a fossa on the posterior wall below the aditus, while the long limb, parallel to the stapes, terminates in the lenticular process.
The stapes' footplate fits into the oval window, secured by the annular ligament, with an obturator foramen connecting its anterior and posterior crura.
The stapes' footplate fits into the oval window, secured by the annular ligament, with an obturator foramen connecting its anterior and posterior crura.
The tensor tympani and stapedius muscles, innervated by the trigeminal and facial nerves, respectively, modulate excessive vibrations, especially from high-frequency sounds.
The tensor tympani and stapedius muscles, innervated by the trigeminal and facial nerves, respectively, modulate excessive vibrations, especially from high-frequency sounds.
The tensor tympani muscle originates from and resides within the superior semicanal of the musculotubular canal, sharing this canal with the auditory tube which occupies the inferior semicanal, separated by a bony partition.
The tensor tympani muscle originates from and resides within the superior semicanal of the musculotubular canal, sharing this canal with the auditory tube which occupies the inferior semicanal, separated by a bony partition.
Flashcards
External Ear
External Ear
Part of the ear comprising the auricle and external acoustic meatus, leading to the tympanic membrane.
Auricle (Pinna)
Auricle (Pinna)
The visible part of the external ear, made of elastic cartilage, that collects sound.
Tympanic Membrane
Tympanic Membrane
A membrane that separates the external ear from the middle ear, also known as the eardrum.
Middle Ear
Middle Ear
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Auditory Ossicles
Auditory Ossicles
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Inner Ear
Inner Ear
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External Acoustic Meatus
External Acoustic Meatus
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Lobule of the Ear
Lobule of the Ear
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Auricle
Auricle
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Tympanic Cavity
Tympanic Cavity
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Eustachian Tube
Eustachian Tube
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Great Auricular Nerve
Great Auricular Nerve
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Ceruminous Glands
Ceruminous Glands
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Pars Flaccida
Pars Flaccida
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Promontory
Promontory
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Cone of Light
Cone of Light
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Facial Nerve Canal
Facial Nerve Canal
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Oval Window
Oval Window
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Round Window
Round Window
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Tegmen Tympani
Tegmen Tympani
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Malleus
Malleus
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Incus
Incus
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Stapes
Stapes
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Tensor Tympani
Tensor Tympani
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Chorda Tympani
Chorda Tympani
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Auditory Tube
Auditory Tube
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Mastoid Antrum
Mastoid Antrum
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Tympanic Plexus
Tympanic Plexus
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Elastic Cartilage
Elastic Cartilage
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Stapedius
Stapedius
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Mucous Membrane of the Middle Ear
Mucous Membrane of the Middle Ear
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Nerve Supply to Middle Ear
Nerve Supply to Middle Ear
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Blood Supply to Middle Ear
Blood Supply to Middle Ear
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Lymph Drainage of Middle Ear
Lymph Drainage of Middle Ear
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Otic Ganglion
Otic Ganglion
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Lesser Petrosal Nerve
Lesser Petrosal Nerve
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Facial Nerve and Ear
Facial Nerve and Ear
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Cell Bodies in Trigeminal Nerve
Cell Bodies in Trigeminal Nerve
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Study Notes
Ear Anatomy
- The ear is divided into three sections: external, middle, and inner.
- The external ear comprises the auricle (pinna) and external acoustic meatus, which leads to the tympanic membrane.
- The middle ear contains auditory ossicles (malleus, incus, stapes) and air, communicating with the nasopharynx via the auditory tube.
- The inner ear consists of the bony labyrinth, housing the membranous labyrinth with auditory and vestibular nerve receptors.
External Ear Structure
- The auricle has resilient yellow elastic cartilage, forming folds for its shape.
- The auricle's skin is hairy on both surfaces.
- The earlobe lacks cartilage, consisting of fibrofatty tissue.
- The cartilaginous external acoustic meatus is stabilized by its attachment to bone.
- Extrinsic muscles in lower animals move the auricle.
- The external acoustic meatus is a curved, 3 cm long tube.
- The tube is straightened for otoscope insertion by pulling the auricle upwards and backwards.
- The tympanic membrane is situated at the meatus's end.
- The outer third of the meatus is cartilage, and the inner two thirds are bone.
- The cartilaginous part holds hairs and ceruminous glands, secreting earwax.
- The meatus is narrowest near the tympanic membrane.
External Ear Vascularization and Innervation
- Blood supply is provided by the posterior auricular and superficial temporal arteries.
- Deeper meatus receives blood from the deep auricular artery (branch of maxillary).
- Corresponding veins drain blood.
- Lymph drainage occurs to occipital, preauricular, and superficial cervical nodes.
- Main cutaneous nerves are the great auricular and auriculotemporal nerves, augmented by possible vagus and facial nerve contributions.
Middle Ear Structure and Function
- Middle ear is an air-filled space in the temporal bone.
- The middle ear transforms sound vibrations from the eardrum (tympanic membrane) to the inner ear.
- The tympanic cavity is a blind diverticulum from the nasopharynx.
- It includes the auditory tube, tympanic cavity, mastoid antrum, and air cells.
- The tympanic membrane is a thin, circular structure (1 cm diameter), angled at 55° to the meatus, creating a cone of light when illuminated.
- The umbo is the small depression marking the tympanic membrane's center.
- It's composed of collagen fibers arranged radially and circumferentially.
- The membrane's tension can be affected by pressure differences.
Middle Ear Ossicles
- Malleus: a club-shaped ossicle, its handle attaches to the tympanic membrane.
- Incus: a larger ossicle between the malleus and stapes.
- Stapes: a small ossicle, its footplate fits into the oval window of the inner ear, transmitting vibrations.
Middle Ear Muscles
- Tensor tympani: arises in the middle ear, attached to the malleus.
- Stapedius: arises in the pyramid, attached to the stapes.
- Both dampen low-frequency vibrations.
Middle Ear Vascularization and Innervation
- Blood supply involves the deep auricular artery (meatal side) and stylomastoid artery (mucosal side).
- Sensory innervation comes from the auriculotemporal nerve, with possible vagus and facial nerve contributions.
- The mucosal surface has tympanic branch of glossopharyngeal nerve innervation (tympanic plexus).
Inner Ear Structure (in relation to middle ear)
- The medial wall of the tympanic cavity faces the inner ear.
- Prominent features include the promontory (cochlea), oval window, and round window.
- The facial nerve and lateral semicircular canal are also present.
- The roof (tegmen tympani) and floor of the cavity are part of surrounding bone structure.
- The anterior, posterior walls and related structures are detailed.
Auditory Tube (Eustachian Tube)
- Connects the middle ear to the nasopharynx, equalizing air pressure.
- Has bony and cartilaginous components, with cartilaginous portion resembling an inverted J.
- Lined with respiratory mucous membrane, and cilia assist in preventing infection.
- Swallowing opens the tube, equalizing pressure.
Mastoid Antrum and Air Cells
- The mastoid antrum is connected to the epitympanic recess within the temporal bone.
- Extensive air cells pneumatize the mastoid process.
- The mastoid antrum and air cells are lined with mucoperiosteum.
Middle Ear Blood Supply and Innervation (summary)
- Numerous arteries and veins supply and drain the middle ear.
- Lymph drainage goes to parotid, retropharyngeal and upper deep cervical nodes.
- The middle ear's mucous membrane is supplied by the tympanic plexus.
Nerve Supply to Middle Ear (Summary from Tympanic Plexus)
- The tympanic plexus is formed mainly by the tympanic branch of the glossopharyngeal nerve.
- It receives sympathetic fibers from the internal carotid nerve.
- It furnishes sensory and vasomotor fibers to the middle ear mucosa.
Facial Nerve and the Ear (Summary)
- Branches of the facial nerve perforate the bone to enter the tympanic plexus.
- The Chorda tympani (a portion of the facial nerve) is relevant to taste and salivary glands
- The chorda tympani exits to the lingual nerve.
Otalgia (Ear Pain)
- Ear pain can refer from other areas supplied by the trigeminal, facial, glossopharyngeal, and vagus nerves.
Overall Summary
- The ear's structure is complex, with interactions between its components.
- Function is centered on sound transmission and equalization of pressure.
- Vascularization and innervation are detailed to provide necessary support.
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Description
Test your knowledge of the anatomy of the external ear, including the external acoustic meatus, auricle, and tympanic membrane. This quiz covers key aspects such as blood supply, nerve supply, and the structure of the tympanic cavity. Perfect for students of anatomy and physiology.
