Lateral skull base
This presentation is the property of its rightful owner.
Sponsored Links
1 / 28

LATERAL SKULL BASE PowerPoint PPT Presentation

  • Uploaded on
  • Presentation posted in: General

LATERAL SKULL BASE. AMOLENDA, Patricia G. Anatomy. Internal auditory canal with the facial nerve Jugular Foramen Foramen lacerum Foramen ovale Foramen spinosum. Clinical Examination. The symptoms of the diseases of the lateral skull base may cause deficits of CN 7, 8, 9, 10, 11

Download Presentation


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Lateral skull base


AMOLENDA, Patricia G.



  • Internal auditory canal with the facial nerve

  • Jugular Foramen

  • Foramen lacerum

  • Foramen ovale

  • Foramen spinosum

Clinical examination

Clinical Examination

  • The symptoms of the diseases of the lateral skull base may cause deficits of CN 7, 8, 9, 10, 11

  • CN testing

    • Oral cavity examination: CN 9 & 12

    • Indirect laryngoscopy: CN 10, recurrent laryngeal nerve

Clinical examination1

Clinical Examination

  • Cochleovestibular Syndrome

    • Sensorineural HL

    • Tinnitus

    • Dysequilibrium and vertigo

Clinical examination2

Clinical Examination

  • Jugular Foramen Syndrome

    • CN 9: palatal deviation

    • CN 10: unilateral vocal cord paralysis and dysphagia

    • CN 12: tongue deviation toward the affected side, lingual atrophy, lingual fasciculations

Clinical examination3

Clinical Examination

  • Petrous Apex Syndrome

    • Triad

      • Purulent otorrhea

      • Stabbing ipsilateral facial pain (Trigeminal nerve irritation)

      • Diplopia (CN 6 palsy in petrous apex abscess)

Imaging studies

Imaging Studies

  • CT Scan

    • Best for defining infiltration and destruction of bony structures

  • MRI

    • Better for defining and differentiating lesions especially tumor and inflammatory processes

  • Conventional Angiography

    • Assess disease processes in close proximity to major vessels

    • Embolization

Surgery of the lateral skull base

Surgery of the Lateral Skull Base

  • Intracranial-intradural

    • Most common: suboccipital and retrosigmoid approach

  • Intracranial-extradural (Transtemporal)

    • Exposes the petrous pyramid through a temporal craniotomy

    • The dura is separated from the surface of the petrous pyramid and elevated away from it with the temporal lobe

    • Used in surgical treatment of temporal bone fractures or tumors of the internal auditory canal

Surgery of the lateral skull base1

Surgery of the Lateral Skull Base

  • Extracranial-extradural (Transmastoid and infratemporal)

Laterobasal fractures

Laterobasal Fractures

Classification of temporal bone fractures

Classification of Temporal Bone Fractures

  • Squama-mastoid Fractures

  • squLongitudinal temporal bone fracture

  • Transverse temporal bone fracture

  • Isolated meatal fracture

Squama mastoid fractures

Squama-mastoid Fractures

  • Confined to the temporal squama and mastoid air cells

  • Auditory and tympanic cavity may also be involved

Isolated meatal fracture

Isolated Meatal Fracture

  • Most often caused by a posterior displacement of the mandibular condyle

  • Usually due to a fall onto the chin

  • The fracture penetrates the posterior wall of the glenoid fossa and the anterior wall of the ear canal and is often associated with a condylar neck fracture

Longitudinal temporal bone fractures

Longitudinal Temporal bone Fractures

  • Most common burst fracture

  • Caused by a diffuse, lateral traumatizing force (ex. Falls, brain trauma)

  • Fracture along the EAC and the anterior border of the petrous pyramid

  • Symptoms: otorrhea (blood or blood with CSF), hearing loss, bloody rhinorrhea, facial paralysis

Longitudinal temporal bone fracture

Longitudinal Temporal Bone Fracture


  • Otoscopy: tearing of the meatal skin and TM, with bleeding into the ear canal

  • Clinical auditory testing (Weber test): lateralized to affected ear

  • Neurography: facial nerve function

  • Thin slice CT scan

  • Pure tone audiometry

Longitudinal temporal bone fracture1

Longitudinal Temporal Bone Fracture


  • Meningitis, OM w/ TM perforation, facial nerve paralysis


  • Cover the ear with sterile dressing

  • Corticosteroids: facial paralysis

  • Surgical exploration

Transverse temporal bone fractures

Transverse Temporal Bone Fractures

  • Fracture that runs across the petrous pyramid along the internal auditory canal and//or through the labyrinth

  • Caused by a traumatizing force in the frontal plane

  • Symptoms: severe vertigo, nausea and vomiting, deafness

Transverse temporal bone fracture

Transverse Temporal Bone Fracture


  • Clinicalexamination:

    • Weber Test-Lateralized to the normal ear

    • spontaneous nystagmus towards normal side

    • Otoscopy: hemotympanum

  • CT Scan

Transverse temporal bone fracture1

Transverse Temporal Bone Fracture


  • Meningitis, Facial nerve paralysis


  • Surgical closure

Inflammations and tumors of the lateral skull base

Inflammations and Tumors of the Lateral Skull Base

Otitis media

Otitis Media

  • most common inflammation and infection that affect the lateral skull base region

  • Cholesteatoma is one of its complications which arises from the middle ear and spreads to the lateral skull base

Tumors of the temporal bone

Tumors of the Temporal Bone

  • Paraganglioma

  • Primary Cholesteatoma or Epidermoid

  • Carcinoma of the Mucosa

  • Sarcoma

  • Lymphoma



  • Also glomustumor, chemodectoma

  • Most common tumor of the middle ear and adjacent lateral skull base

  • Arises from the paraganglia of the temporal region, most commonly in the area of the jugular bulb and along the neural plexus of the tympanic cavity

  • It may be located in the middle ear, jugular bulb, carotid bifurcation, and along the vagus nerve, and often extend to the temporal bone region



  • Manifestations: pulsatile tinnitus and conductive hearing loss, possible SNHL

  • Diagnosis: MRI, CT Scan, Angiography

  • Treatment: Surgery-subtotal petrosectomy

Tumors of the internal auditory canal and cerebellopontine angle

Tumors of the Internal Auditory Canal and Cerebellopontine Angle

  • Vestibular Schwanomma

  • Meningioma

  • Hemangioma

  • Lipoma

Vestibular schwanomma

Vestibular Schwanomma

  • Slow-growing, benign, tumor arising from the Schwann cells of CN 8, affecting more commonly the vestibular nerve

  • Medial tumors arise from the intracranial part of CN8 while the lateral tumors are located in the internal auditory canal

  • Clinical hallmark is a unilateral hearing disorder which may consist of tinnitus, hearing loss and dysacusis

Vestibular schwannoma

Vestibular Schwannoma

  • Medial schwannomas can occasionally produce trigeminal nerve symptoms such as facial pain or numbness in the jaw

  • Large tumors present with signs of brainstem compression and/or hydrocephalus with ataxia, nausea & vomiting

  • Diagnosis:

    • clinical examination: shows unilateral cochleovestibular d/o

    • Audiometry: shows retrocochlear impairment with lengthening of auditory brainstem reposnses

    • gadolinium enhanced MRI

Vestibular schwanomma1

Vestibular Schwanomma

  • <1cm: observe

  • 1-2.5cm: streotactic radiosurgery/ open surgery

  • >2.5cm: open surgery

  • Login