External Ear Anatomy Quiz

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Questions and Answers

What structure follows the intertragic notch in the ear anatomy?

Cymba conchae

Antitragus

Tragus (correct)

Concha

Which part of the ear is located above the antitragus?

Eustachian tube

Concha

Intertragic notch

Cymba conchae (correct)

What are the two subdivisions of the area bounded by the antitragus?

Cymba conchae and antitragus

Tragus and concha

External canal and tragus

Cymba conchae and concha (correct)

Which of the following is located below the cymba conchae?

Concha Signup and view all the answers

What anatomical feature is present in front of the antitragus?

Intertragic notch Signup and view all the answers

What is continuous with the cartilage of the meatus?

The cartilage of the external ear Signup and view all the answers

What are the fissures of Santorini associated with?

The entry of infections from certain regions Signup and view all the answers

Which regions do the fissures of Santorini primarily affect?

The parotid and superficial mastoid regions Signup and view all the answers

What role does the cartilage of the meatus play in relation to infections?

It serves as a pathway for infection entry Signup and view all the answers

What is the primary structural feature of the cartilage of the meatus?

It is continuous with another cartilage Signup and view all the answers

What is the name of the nerve that enters the middle ear through the small aperture near the medial border of the floor?

Glossopharyngeal nerve (IX) Signup and view all the answers

Which of the following anatomical features is associated with the entry point of the tympanic branch from the glossopharyngeal nerve?

Medial border of the floor Signup and view all the answers

What is the primary function of the tympanic branch of the glossopharyngeal nerve as it enters the middle ear?

Carrying sensory information from the middle ear Signup and view all the answers

Which of the following statements is true regarding the glossopharyngeal nerve and its role in the ear?

It contributes to both sensory and motor functions related to the ear. Signup and view all the answers

Where is the tympanic branch of the glossopharyngeal nerve primarily situated before entering the middle ear?

Near the medial border of the middle ear floor Signup and view all the answers

What is the primary function of the structure associated with the middle ear regarding pressure?

To equalize pressure in the middle ear with atmospheric pressure Signup and view all the answers

What allows the tympanic membrane to move freely?

Equalized pressure in the middle ear Signup and view all the answers

Which of the following is NOT a function of the structure associated with the middle ear?

Facilitation of sound transmission Signup and view all the answers

What type of pathogens is the middle ear structure particularly designed to protect against?

Pathogens and secretions from the nasopharynx Signup and view all the answers

What is the consequence of failure to equalize pressure in the middle ear?

Impaired movement of the tympanic membrane Signup and view all the answers

What is the approximate transformer ratio of the middle ear?

18:1 Signup and view all the answers

How much sound amplification does the transformer ratio translate to in decibels?

25 dB Signup and view all the answers

What two factors contribute to the transformer ratio in the middle ear?

The tympanic membrane and the lever action of the ossicles Signup and view all the answers

What is the calculated multiplication factor of the area effect of the tympanic membrane and the lever action of the ossicles?

14 × 1.3 Signup and view all the answers

Why is the transformer ratio significant for hearing?

It increases the sound level reaching the inner ear. Signup and view all the answers

Where does the horizontal portion of the facial nerve lie in relation to the oval window?

Just above the oval window Signup and view all the answers

What anatomical structure is positioned above the second genu of the facial nerve?

The ampullary end of the horizontal semicircular canal Signup and view all the answers

Which statement correctly describes the relationship between the facial nerve and the horizontal semicircular canal?

The ampullary end of the horizontal semicircular canal lies just above the facial nerve Signup and view all the answers

In anatomical positioning, where would one find the horizontal portion of the facial nerve?

In its bony canal, above the oval window Signup and view all the answers

What is the correct positional relationship of the facial nerve to other structures in this anatomical region?

Just above the ampullary end of the horizontal semicircular canal Signup and view all the answers

Study Notes

External Ear

The external ear, also known as the pinna, is largely composed of elastic cartilage.
It's covered by skin on both the outer and inner surfaces.
The lowest part of the auricle is called the lobule and is soft.
The auricle has a curved ridge called the antihelix, a ridge called the helix, and a depression called the concha.
The antitragus and tragus are parts of the auricle.
Darwin's tubercle is a small elevation on the helix.
The external ear is supplied by the superficial temporal artery and posterior auricular artery.
Lymphatic drainage from the ear is to the pre-auricular, post-auricular, superficial cervical lymph nodes.
The upper two-thirds of the external ear's lateral surface is supplied by the auriculotemporal nerve. The lower third is supplied by the great auricular nerve.
The medial two-thirds of the lateral surface is supplied by the lesser occipital nerve, and the lower third by the great auricular nerve.
The root of the auricle is supplied by the auricular branch of the vagus nerve.

External Auditory Canal (EAC)

The EAC extends from the concha to the tympanic membrane.
Its course is primarily medial with tendency to go forward, upward, and downward.
It's approximately 24-25mm long.
The medial two-thirds of the canal are bony, while the lateral third is cartilaginous.
The skin lining the bony part is thin and firmly attached, and thick on the cartilaginous part.
The cartilaginous portion contains sebaceous and ceruminous glands.
The canal has a narrow portion called the isthmus, which lies 6 mm lateral to the tympanic membrane.
The deficient part of the ring of the cartilaginous portion is completed by fibrous tissue
The isthmus is a potential site for foreign body impaction and infections.
It remains patent (open) up to the age of 4 years, and is closed in adults.

Middle Ear

The middle ear is an air-filled cavity behind the eardrum, with respiratory epithelium lining the Eustachian tube and antero-inferior part of the cavity.
The Eustachian tube connects the middle ear cavity to the nasopharynx.
The tube is partially bony and partially cartilaginous.
It opens on yawning or swallowing.
The tube equalizes middle ear pressure with atmospheric pressure, clears secretions, shields the middle ear from sounds and pathogens from the nasopharynx.
The tympanic cavity is divided into different parts: mesotympanum, epitympanum, and hypotympanum.
The middle ear also contains three auditory ossicles: malleus, incus, and stapes which transmits vibrations from the eardrum to the inner ear. These bones form an ossicular chain from the eardrum to the oval window.
The middle ear also contains the stapedius and tensor tympani muscles, which control the movement of the ossicles and protect the inner ear from excessive sound vibrations.
The Chorda tympani nerve runs through the middle ear cavity.
The middle ear also contains the mastoid antrum.

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Description

Test your knowledge of the anatomy of the external ear, also known as the pinna. This quiz covers the various components, blood supply, and nerve innervation of the external ear. Perfect for students studying human anatomy or related fields.