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MCQs on Temporal Bone Anatomy – For NEET PG & University Exams

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ENT MCQs on Temporal Bone Anatomy – For NEET PG & University Exams

1. A 45-year-old male presents with diplopia, retroorbital pain, and a history of chronic otitis media with discharge. On exam, he has lateral rectus palsy. Which part of the temporal bone is most likely affected?

A. Squamous part
B. Petrous apex
C. Tympanic part
D. Mastoid process

2. The pterion, the weakest part of the skull, is formed by the junction of all of the following bones except:

A. Frontal
B. Temporal (Squamous)
C. Occipital
D. Parietal

3. Which muscle originates from the lateral surface of the squamous part of the temporal bone?

A. Temporalis
B. Masseter
C. Sternocleidomastoid
D. Digastric (posterior belly)

4. The tegmen tympani is a bony plate located on the:

A. Lateral wall of external auditory canal
B. Inferior surface of petrous bone
C. Anterior surface of petrous part
D. Posterior wall of tympanic cavity

5. A surgeon performing a postauricular mastoidectomy in a child must avoid injuring a nearby nerve that exits at the stylomastoid foramen. This nerve is:

A. Vagus
B. Facial
C. Glossopharyngeal
D. Trigeminal

6. A CT scan reveals an erosion at the arcuate eminence. Which structure lies just beneath this elevation?

A. Cochlear duct
B. Horizontal semicircular canal
C. Superior semicircular canal
D. Vestibular aqueduct

7. A 25-year-old man has a fracture involving the tympanic part of the temporal bone. Which of the following symptoms is most likely?

A. Vertigo due to vestibular dysfunction
B. Paralysis of facial muscles
C. Conductive hearing loss
D. Diplopia due to VI nerve palsy

8. The fundus of the internal acoustic meatus is divided into upper and lower compartments by:

A. Petrosquamous suture
B. Annular sulcus
C. Horizontal crest
D. Arcuate eminence

9. Which of the following passes through the stylomastoid foramen?

A. Greater petrosal nerve
B. Vestibulocochlear nerve
C. Facial nerve
D. Arnold’s nerve

10. The sigmoid sinus lies in close relation to which part of the temporal bone?

A. Squamous
B. Mastoid (medial surface)
C. Styloid
D. Tympanic

11. A patient presents with pulsatile tinnitus. Imaging shows a lesion near the jugular fossa. Which surface of the petrous temporal bone is involved?

A. Superior
B. Posterior
C. Inferior
D. Anterior

12. In mastoidectomy, which septum separates the squamous and petrous parts of the mastoid bone?

A. Pterygoid septum
B. Korner’s septum
C. Gruber’s ligament
D. Annular ring

13. The tympanic membrane is attached to the bony groove called:

A. Petrotympanic fissure
B. Annular sulcus
C. Jugular fossa
D. Facial canal

14. The stylomandibular ligament:

A. Lies between the stylopharyngeus and pharyngeal constrictors
B. Separates the parotid and submandibular glands
C. Extends from mastoid to angle of mandible
D. Pierces the stylomastoid foramen

15. The internal auditory meatus transmits all the following except:

A. Facial nerve
B. Vestibulocochlear nerve
C. Labyrinthine artery
D. Chorda tympani nerve

 

Answer Key with Detailed Explanations

1. B. Petrous apex. The petrous apex of the temporal bone is the site involved in Gradenigo’s syndrome, a complication of chronic otitis media. It is characterized by the triad:

  • Persistent otorrhea (discharging ear),
  • Retro-orbital pain (due to trigeminal nerve involvement),
  • Lateral rectus palsy (due to abducens nerve involvement). The VI cranial nerve (abducens) runs close to the petrous apex, making it vulnerable to inflammation here.

2. C. Occipital. The occipital bone lies posteriorly and is not part of the pterion. The pterion is the thinnest and weakest area of the lateral skull. It is formed by the junction of:

  • Frontal bone,
  • Parietal bone,
  • Squamous temporal bone, and
  • Greater wing of the sphenoid.

3. A. Temporalis. The temporalis muscle originates from the temporal fossa, which includes the squamous part of the temporal bone. This muscle passes under the zygomatic arch and inserts on the coronoid process of the mandible, aiding in jaw elevation. Other options, like the sternocleidomastoid and digastric, do not originate from the squamous part.

4. C. Anterior surface of petrous part. The tegmen tympani is a thin bony plate that forms the roof of the middle ear cavity. It lies on the anterior surface of the petrous part of the temporal bone, separating the middle ear from the middle cranial fossa (important in CSF leaks and meningitis).

5. B. Facial nerve. The facial nerve (CN VII) exits the skull through the stylomastoid foramen, located between the styloid and mastoid processes. During mastoidectomy, especially in children (where the mastoid is underdeveloped), there is a risk of facial nerve injury. Facial nerve palsy can result if not carefully identified and preserved.

6. C. Superior semicircular canal. The arcuate eminence is a bony prominence on the anterior surface of the petrous part of the temporal bone. It represents the underlying superior semicircular canal. It is an important surgical landmark in middle cranial fossa approaches.

7. C. Conductive hearing loss. The tympanic part of the temporal bone contributes to the walls and floor of the external auditory canal (EAC). A fracture here may disrupt the EAC, leading to conductive hearing loss. It does not affect the inner ear (no vertigo) or facial nerve directly unless the fracture extends deeper.

8. C. Horizontal crest. The internal acoustic meatus (IAM) is divided by the horizontal (transverse) crest into:

  • Superior compartment – for facial nerve and superior vestibular nerve
  • Inferior compartment – for cochlear nerve and inferior vestibular nerve
    This bony crest helps in orientation during skull base surgery and radiological interpretation.

9. C. Facial nerve. The facial nerve exits the temporal bone via the stylomastoid foramen, after passing through the facial canal. It gives branches to muscles of facial expression, and injuries at this exit point lead to peripheral facial palsy. The greater petrosal nerve exits earlier at the hiatus, and the vestibulocochlear nerve exits through the internal acoustic meatus.

10. B. Mastoid (medial surface). The sigmoid sinus is a dural venous sinus that travels through the sigmoid sulcus on the medial aspect of the mastoid part of the temporal bone. This region is important during mastoid surgeries; injury can lead to massive venous bleeding or sigmoid sinus thrombosis.

11. C. Inferior. The jugular fossa, housing the jugular bulb, is located on the inferior surface of the petrous part of the temporal bone. Lesions here can present with pulsatile tinnitus due to venous flow near the middle ear. Tumors like glomus jugulare arise from this region.

12. B. Korner’s septum. Korner’s septum is a bony plate that separates the squamous part from the mastoid (petrous) part of the temporal bone. It is an extension of the posterior wall of the bony external auditory canal. Incomplete removal during mastoidectomy can lead to residual disease.

13. B. Annular sulcus. The annular sulcus is a groove in the tympanic part of the temporal bone that holds the tympanic membrane (TM) via the annulus. Proper placement here is essential during myringoplasty or tympanoplasty.

14. B. Separates the parotid and submandibular glands. The stylomandibular ligament runs from the styloid process to the angle of the mandible. It acts as a boundary between the parotid gland (posterior) and the submandibular gland (anterior). It is considered a thickened band of deep cervical fascia.

15. D. Chorda tympani nerve. The internal acoustic meatus (IAM) transmits:

  • Facial nerve (CN VII),
  • Vestibulocochlear nerve (CN VIII),
  • Labyrinthine artery (branch of AICA).
    The chorda tympani is a branch of facial nerve that arises in the facial canal and exits through the petrotympanic fissure, not via IAM.

———— End of the chapter ————

 

Reference Textbooks.

  • Scott-Brown, Textbook of Otorhinolaryngology-Head and Neck Surgery.
  • Glasscock-Shambaugh, Textbook of Surgery of the Ear.
  • P L Dhingra, Textbook of Diseases of Ear, Nose and Throat.
  • Hazarika P, Textbook of Ear Nose Throat And Head Neck Surgery Clinical Practical.
  • Mohan Bansal, Textbook of Diseases of Ear, Nose and Throat Head and Neck Surgery
  • Hans Behrbohm, Textbook of Ear, Nose, and Throat Diseases With Head and Neck Surgery.
  • Salah Mansour, Middle Ear Diseases – Advances in Diagnosis and Management.
  • Logan Turner, Textbook of Diseases of The Nose, Throat and Ear Head And Neck Surgery.
  • Rob and smith, Textbook of Operative surgery.
  • Anirban Biswas, Textbook of Clinical Audio-vestibulometry.
  • Arnold, U. Ganzer, Textbook of  Otorhinolaryngology, Head and Neck Surgery.

Author:

Dr. Rahul Bagla ENT Textbook

Dr. Rahul Bagla
MBBS (MAMC, Delhi) MS ENT (UCMS, Delhi)
Fellow Rhinoplasty & Facial Plastic Surgery.
Renowned Teaching Faculty
Mail: msrahulbagla@gmail.com
India

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