Disorders in the middle ear

What are the three bones in the ossicular chain?

Malleus, incus, stapes

What is the function of the Eustachian tube in the middle ear?

it connects the middle ear to the nasopharynx and supplies air to the middle ear

Name the two muscles found in the middle ear

Stapedius and Tensor Tympani 

1. What is the typical diameter of the tympanic membrane (TM)?
   A) 1–3 mm
   B) 5–7 mm
   C) 8–10 mm
   D) 12–14 mm

C) 8–10 mm

2. Which of the following is NOT one of the three layers of the tympanic membrane?
   A) Epidermal (derived from ectoderm)
   B) Cartilaginous (derived from perichondrium)
   C) Fibrous (lamina propria)
   D) Membranous

B) Cartilaginous (derived from perichondrium)

What is the function of the umbo on the tympanic membrane?
A) Amplifies high-frequency sounds
B) Serves as the point of maximum concavity
C) Connects the incus and stapes
D) Anchors the eustachian tube

B) Serves as the point of maximum concavity

4. Which part of the malleus is directly attached to the tympanic membrane?
   A) Head
   B) Neck
   C) Manubrium
   D) Handle

C) Manubrium

5. Which ossicle is the smallest bone in the human body?
   A) Malleus
   B) Incus
   C) Stapes
   D) Umbo

C) Stapes

What is the primary function of the annular ligament?
A) Transmits sound waves to the cochlea
B) Supports the stapes in the oval window
C) Connects the malleus and incus
D) Anchors the tympanic membrane

B) Supports the stapes in the oval window

What is the primary function of the tensor tympani muscle?
A) Tenses the tympanic membrane by pulling on the malleus
B) Opens the Eustachian tube
C) Vibrates to transmit sound to the cochlea
D) Attaches the stapes to the oval window

A) Tenses the tympanic membrane by pulling on the malleus

Which muscle is the smallest in the human body?
A) Tensor tympani
B) Levator veli palatini
C) Stapedius
D) Tensor veli palatini

C) Stapedius

Which of the following is NOT a main function of the Eustachian tube?
A) Transmission of neural signals to the cochlea
B) Ventilation of the middle ear
C) Protection from nasopharyngeal secretions
D) Clearance of middle ear secretions

A) Transmission of neural signals to the cochlea

Which of the following is NOT a main function of the Eustachian tube?
A) Transmission of neural signals to the cochlea
B) Ventilation of the middle ear
C) Protection from nasopharyngeal secretions
D) Clearance of middle ear secretions

A) Transmission of neural signals to the cochlea

What causes the Eustachian tube to open?
A) Changes in sound frequency
B) Activation of the stapedius muscle
C) Changes in atmospheric pressure, swallowing, yawning, sneezing
D) Stimulation of the cochlear nerve

C) Changes in atmospheric pressure, swallowing, yawning, sneezing

Which muscle helps elevate and pull back the soft palate during swallowing and yawning?
A) Tensor tympani
B) Levator veli palatini
C) Tensor veli palatini
D) Stapedius

B) Levator veli palatini

Which cranial nerve innervates the tensor veli palatini muscle?
A) CN VII (Facial)
B) CN V (Trigeminal – mandibular branch V3)
C) CN IX (Glossopharyngeal)
D) CN X (Vagus)

B) CN V (Trigeminal – mandibular branch V3)

What is one of the main roles of the Eustachian tube during yawning or chewing?
A) Vibrate the tympanic membrane
B) Protect the cochlea from loud sounds
C) Equalize middle ear pressure
D) Amplify sound waves

C) Equalize middle ear pressure

What are the main functions and international of the tensor veli palatini muscle?

• Contracts during yawning, swallowing, and chewing to open the Eustachian tube and equalize pressure.

• Tenses the soft palate during swallowing.

• Origin: Cartilaginous portion of the Eustachian tube.

• Insertion: Posterior border of the soft palate.

• Innervation: Mandibular branch (V3) of the trigeminal nerve (CN V), which also innervates six of the seven muscles involved in mastication.

What can happen if the Eustachian tube does not close versus when it does not open or is blocked?

• If it does not close: The tube remains abnormally patent, leading to a condition called patulous Eustachian tube.

• If it does not open or is blocked:
  

  • Air in the middle ear is absorbed, creating a vacuum.

  • Negative pressure causes retraction of the tympanic membrane.

  • This can result in middle ear diseases.

Why are children more likely to experience Eustachian tube dysfunction compared to adults?

• Size: The Eustachian tube does not reach adult size until about 7 years old.

• Slope: In children, the tube has a 10° slope from the horizontal plane (compared to 45° in adults), making drainage and pressure regulation less efficient.

What is the primary function of the middle ear in terms of energy transfer?

the middle ear acts as a mechanical connection between the tympanic membrane and the oval window, creating a more efficient energy transfer system than if no middle ear system were present. This is known as an impedance matching system. 

What does the impedance matching system do?

It provides efficient delivery of energy from the air filled middle ear to the fluid filled inner ear by overcoming the difference in impedance between air and fluid 

What is impedance?

the opposition to the flow of energy, and it differs between air and fluid

What are the two main types of imaging used for the Brain and auditory system?

Computed Tomography (CT) scan and Magnetic Resonance Imaging (MRI)

What is the role of a radiologist in a multidisciplinary team?

A medical doctor who specializes in acquiring and interpreting medical images

what is the primary role of a neuroradiologist?

specializes in acquiring and interpreting images of the nervous system.

what does the coronal plane divide the body into?

Front and back sections

What does the midsagittal plane divide the body into?

Right and left sections

What does the axial plane divide the body into?

upper and lower sections

What does a CT scanner measure to create images?

the amount of energy absorbed by the head when exposed to radiation (X-rays)

What was the age range and demographic of participants in the CT scanner expectation survey?

Ages 35-65, predominantly white, married, health-conscious individuals with income and education levels above the national average 

What percentage of participants reported learning about CT scans from a physician?

1/5 (20%) of participants 

What is a significant association revealed by the Chi-Square Test for independence in CT scan expectation?

A significant association between level of personal health concern and the expectation that a scan could improve overall health

What type of imaging is typically used to visualize the temporal bone?

Computed Tomography (CT)

What does MRI measure to generate images?

The detected energy of protons released as they realign with the magnetic field

Which of the following is NOT a common cause of tympanic membrane perforation?

A. Otitis media

B. Flying objects

C. Noise exposure below 60 dB SPL

D. Temporal bone fracture

C. Noise exposure below 60 dB SPL

True or False: Most tympanic membrane perforations heal spontaneously, but some may persist due to chronic infection.

True

Tympanic membrane perforations most often occur near which areas?

A. Pars flaccida and pars tensa

B. Round window and oval window

C. Cochlea and semicircular

D. Eustachian tube opening 

Pars flaccida and pars tensa 

What is the approximate rupture threshold of the tympanic membrane in humans?

A. 84 dB SPL

B. 100 dB SPL

C. 184 dB SPL

D. 250 dB SPL

C. 184 dB SPL

What is a cholesteatoma?

A group of keratin-producing squamous epithelial cells in the middle ear or mastoid. It is NOT a neoplasm 

Which of the following can lead to cholesteatoma formation?

A. Chronic tympanic membrane perforation

B. Erosion of the ossicles

C. Granulation tissue in the middle ear (bumpy skin under first layer of skin)

D. All of the above

D. All of the above.

what is the difference between congenital and acquired cholesteatoma?

• Congenital: Occurs without a history of otitis media, tympanic membrane perforation, or Eustachian tube dysfunction.

• Acquired: Results from retraction of the tympanic membrane or migration of squamous cells through a perforation.

Which of the following is a common early symptom of

Cholesteatoma?

A. Sudden sensorineural hearing loss

B. Patients are usually asymptomatic until ossicles are impacted

C. Severe vertigo

D. Pulsatile tinnitus

B. Patients are usually asymptomatic until ossicles are impacted

What type of hearing loss occurs when ossicles are impacted by cholesteatoma?

Conductive hearing loss in the affected ear

Secondary cholesteatoma with bacterial colonization is commonly associated with:

A. Clear drainage

B. Bloody otorrhea

C. Foul-smelling otorrhea with chronic inflammation

D. Pulsatile tinnitus

B. Foul-smelling otorrhea with chronic inflammation

What is a characteristic appearance of cholesteatoma debris?

It appears like white cake frosting

Which of the following complications can results from cholesteatoma?A. Erosion of ossicles

B. Damage to facial nerve

C. Meningitis

D. All of the above

D. All of the above

name at least three serious complications that can occur if a cholesteatoma is left untreated.

• Facial nerve paralysis

• Erosion of horizontal semicircular canal

• Meningitis

• Brain abscess

• Subdural empyema

What is the average age of diagnosis for congenial cholesteatoma?

B. 5.6 years

What is the incidence rate of acquired cholesteatoma in children?

About 3 per 100,000 children

What causes a congenital cholesteatoma?

Remaining embryonic epithelial cells trapped in the middle ear

What is the main cause of an acquired cholesteatoma?

Chronic otitis media and Eustachian tube dysfunction causing invagination of squamous epithelium from a retracted tympanic membrane.

Which region is adjacent to the tympanic membrane?

A. Epitympanum

B. Mesotympanum

C. Hypotympanum

D. Protympanum

B. Mesotympanum 

What space is most commonly involved in acquired cholesteatoma?

The posterior epitympanum space, also known as Prussak’s space.

Which ossicles are most easily eroded by a cholesteatoma?

The malleolus and the head of the incus.

Whay type of hearing loss is typically associated with cholesteatoma?

A. Conductive

B. Mixed

C. Sensorineural

D. Central

A. Conductive 

Will patients with cholesteatoma usually have a history of sensorineural hearing loss before diagnosis?

No. There is typically no previous SNHL, only a purely conductive component. 

What diagnostic tool is commonly used to assess middle ear function in cholesteatoma?

Tympanometry

What imaging method is often used to evaluate the extent of a cholesteatoma?

CT scan of the temporal bone.

Which of the following may extend into the external auditory canal with cholesteatoma?

A. Cerumen

B. Granulated tissue or polyp

C. Ossicular chain

D. TM membrane debris

B. Granulated tissue or polyp

Name two non-surgical management strategies for cholesteatoma?

• Steroid drops

• Placement of a PE tube to prevent TM retraction

• Avoiding water exposure to reduce bacterial growth

What is the main purpose of surgical intervention in cholesteatoma?

A. Reduce tinnitus

B. Create a safe, dry ear and restore hearing

C. Improve Eustachian tube function

D. Prevent ossicular regrowth

B. Create a safe, dry ear and restore hearing

What type of surgical procedure is typically performed to remove cholesteatoma?

A canal wall-up (CWU) mastoidectomy