HN 23. The ear: external ear, middle ear and internal ear
Anatomy, MBBS Second Year. This chapter is split into 4 topics and has
193 practice questions. The topics covered are listed below, followed by
10 free sample questions from the chapter.
Topics in this chapter
The external ear: auricle, meatus and tympanic membrane51 questions
The middle ear: boundaries41 questions
Contents of the middle ear, its muscles and otitis media51 questions
The Eustachian tube and the internal ear50 questions
Sample questions: HN 23. The ear: external ear, middle ear and internal ear
10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.
Q1. Which three arteries supply the external auditory meatus?
A. The internal carotid, ophthalmic and lacrimal arteries
B. The occipital, lingual and facial arteries
C. The anterior auricular artery (superficial temporal), the posterior auricular artery (external carotid) and the deep auricular artery (maxillary)(correct answer)
D. The anterior tympanic, deep auricular and posterior tympanic arteries
Answer: C.Arterial supply of the external auditory meatus: (1) anterior auricular artery (from the superficial temporal artery); (2) posterior auricular artery (from the external carotid); (3) deep auricular artery (from the maxillary artery).
Q2. Which statement about the external ear is correct?
A. It comprises the ossicles and the Eustachian tube
B. It comprises the auricle (elastic cartilage, 5 parts, supplied by auriculotemporal/great auricular/vagal/facial nerves), the S-shaped 2.5 cm meatus (cartilaginous outer third with wax glands, bony inner two-thirds) and the tympanic membrane (3 layers, pars flaccida and pars tensa)(correct answer)
C. The meatus is 4 cm long and straight
D. The tympanic membrane has two layers
Answer: B.External ear: auricle (elastic cartilage + skin; helix, antihelix, concha, tragus, lobule; outer-surface nerves — auriculotemporal, great auricular, vagus, facial; inner-surface — lesser occipital and great auricular); external auditory meatus (2.5 cm, S-shaped; cartilaginous outer third with wax glands; bony inner two-thirds); tympanic membrane (3 layers; pars flaccida upper 1/6 without fibrous layer; pars tensa 5/6; umbo; cone of light in the anteroinferior quadrant).
Q3. Which statement about the walls of the middle ear is correct?
A. Roof — tegmen tympani; floor — jugular fossa/IJV; lateral — tympanic membrane; medial — promontory, oval window (stapes), round window (secondary tympanic membrane) and the horizontal facial canal; anterior/posterior — each with a tendon, tube and nerve(correct answer)
B. The medial wall is formed by the tympanic membrane
C. The roof contains the Eustachian tube
D. The lateral wall contains the promontory
Answer: A.Middle ear boundaries: roof — tegmen tympani; floor — jugular fossa and internal jugular vein; lateral wall — tympanic membrane; medial wall — promontory (cochlea), oval window (foot of stapes) above, round window (secondary tympanic membrane) below and the horizontal part of the facial canal; anterior wall — tensor tympani tendon, Eustachian tube, chorda tympani; posterior wall — stapedius tendon, mastoid antrum, chorda tympani and vertical facial canal.
Q4. Which of the following is NOT a boundary (wall) of the middle ear?
A. The tegmen tympani
B. The round window(correct answer)
C. The jugular fossa
D. The tympanic membrane
Answer: B.The round window lies on the medial wall (closed by the secondary tympanic membrane) rather than forming a boundary itself; the boundaries are the roof (tegmen tympani), floor (jugular fossa/IJV), lateral wall (tympanic membrane), medial wall (with the two windows) and the anterior and posterior walls.
Q5. Which comparison of the tensor tympani and stapedius is correct?
A. Both insert into the stapes
B. The stapedius inserts into the malleus
C. The tensor tympani inserts into the malleus and is supplied by the mandibular nerve, while the stapedius inserts into the neck of the stapes and is supplied by the facial nerve(correct answer)
D. Both are supplied by the facial nerve
Answer: C.Tensor tympani: origin — cartilage of the auditory tube, insertion — malleus, nerve — mandibular nerve. Stapedius: origin — pyramidal eminence, insertion — neck of the stapes, nerve — facial nerve. Both damp vibration in response to loud noise.
Q6. Which complications of otitis media are listed?
A. Only deafness
B. Loss of smell and taste
C. Only mastoiditis
D. Rupture of the tympanic membrane (may lead to deafness), mastoiditis, labyrinthitis, meningitis or brain abscess, and facial nerve paralysis(correct answer)
Answer: D.Complications of otitis media: (1) rupture of the tympanic membrane — may lead to deafness; (2) extension to the mastoid process — mastoiditis; (3) extension to the inner ear — labyrinthitis; (4) extension to the cranial cavity — meningitis or brain abscess; (5) extension to the facial nerve — facial paralysis.
Q7. Which statement about the contents of the middle ear is correct?
A. It contains the cochlea and semicircular canals
B. It contains 3 ossicles (malleus, incus, stapes), 2 muscles (tensor tympani, stapedius) and 2 nerves (chorda tympani and the tympanic plexus on the medial wall)(correct answer)
C. It contains the auricle and tympanic membrane
D. It contains one muscle and three nerves
Answer: B.Contents of the middle ear: 3 ossicles (malleus, incus, stapes); 2 muscles (tensor tympani, stapedius); 2 nerves (chorda tympani and the tympanic plexus on the medial wall, formed by the tympanic branch of IX, the caroticotympanic nerve and a communicating branch of the facial nerve).
Q8. Which statement about the internal ear is correct?
A. It is filled with air
B. It comprises a bony labyrinth (perilymph; cochlea, vestibule, 3 semicircular canals) and a membranous labyrinth (endolymph; cochlear duct with the organ of Corti, utricle and saccule with the macula, and semicircular ducts with the crista ampullaris)(correct answer)
C. It comprises the ossicles and the Eustachian tube
D. It contains only the organ of Corti
Answer: B.Internal ear: bony labyrinth (perilymph — cochlea, vestibule and three semicircular canals) and membranous labyrinth (endolymph — cochlear duct/organ of Corti, utricle and saccule/sensory macula, semicircular ducts/crista ampullaris).
Q9. Which statement about the Eustachian tube is correct?
A. It is 2.5 cm long and connects the middle ear with the mastoid antrum
B. It is filled with perilymph
C. It is 4 cm long, has a cartilaginous anterior two-thirds and a bony posterior one-third, connects the tympanic cavity with the nasopharynx, is supplied by the tympanic plexus (IX), and ventilates and equalises pressure in the middle ear(correct answer)
D. It carries the chorda tympani
Answer: C.Eustachian tube: length 4 cm (36 mm); parts — cartilaginous anterior 2/3 and bony posterior 1/3; connects the tympanic cavity with the nasopharynx (opening into the anterior wall of the middle ear); nerve supply — tympanic plexus (IX nerve); functions — ventilation of the middle ear and equalisation of air pressure on each side of the tympanic membrane.
Q10. Which statement summarises the ear as a whole?
A. The external ear (auricle, meatus, tympanic membrane) collects sound; the middle ear (boundaries, ossicles, muscles, nerves, Eustachian tube) transmits and equalises it; the internal ear (bony and membranous labyrinths) converts it into hearing and balance(correct answer)
B. The middle ear contains the cochlea
C. The internal ear contains the ossicles
D. The ear comprises only the auricle and cochlea
Answer: A.External ear — auricle, external auditory meatus and tympanic membrane (sound collection); middle ear — boundaries, contents (ossicles, muscles, nerves) and Eustachian tube (sound transmission and pressure equalisation); internal ear — bony and membranous labyrinths (hearing via the organ of Corti and balance via the maculae and cristae).