base of skull

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BASE OF SKUL

Dr Edward ChegeR1

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OUTLINE

•

Introduction• Clinical significance

• Developmental anatomy

• Anterior skull base

• Central skull base

•

Posterior skull base

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Clinical significanc

•

Fracture base of skull.•  Trans-sphenoidal surgery.

• Intracranial disease spread thro

foramina.

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Developmental anato• Desmocranium

• Chondrocranium

• Ossification

• Fusion of ossification centers

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Plain radiographs

Views1. Lateral view

ATLS

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•

Submento-vertical•  

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Sella turcica view

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Townes view (fronto-occipital 30o c

Sella turcica projected over

foramen Magnum.

Lower radiation dose

to sensitive structures

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Anterior skull baseFloor of anterior cranial fossa

Development

Ø Multiple ossification centers main

endochondral

Ø

Ossification progresses from poste

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Anterior skull baseLimits

Ø Anterior: Frontal boneanteromedially

Ø Posterior: Planum

sphenoidale and Sphenoid

ridge posteriorly

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Anterior skull baseForamina and fissures

1. Foramen caecum

anterior to crista galli

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Anterior skull base2. Anterior ethmoidal foramen

anterior ethmoid artery vein & nerve

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Anterior skull baseØ

Posterior ethmoidal foramepost ethmoid artery vein & nerve

Ø Foramina of cribriform plate

Afferent fibers to olfactory bulb

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Anterior skull baseStructures

Frontal lobe

Olfactory bulb and CN 1,

Optic nerve

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Central skull baseFloor of middle

cranial fossa

Limits

Ø Anterior: Tuberculum sellae,lesser wing of sphenoid

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Central skull baseForamina

Optic canal

Ø CN 2

Sup orbital fissureØ CN 3, 4, 5(i), 6,

Ø superior ophthalmic vein

Inferior orbital fissure

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Central skull baseForamina Cont’d

Carotid canal

Internal carotid and

sympathetic plexus

Foramen rotudum

 To pterygoid fossa

Maxillary branch of CN 5

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Central skull baseForamina

Foramen ovale

Mandibular branch of CN 5

Foramen spinosumMiddle meningeal artery and vein

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Central skull baseForamina

Foramen lacerum

Cartilaginous floor of horizontal

internal carotid artery canal

Vidian canal

Vidian artery and nerve

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Central skull baseNormal Variants

1. Persistent craniopharyngeal canal

Remnant of Rathkes pouch

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Central skull baseExtensive pneumatization of sphen

sinus

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Central skull baseForamen of Vesalius

transmits emissary vein from cavernoto pterygoid plexus

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Posterior skull basBones 

1.  Temporal bones posterior to spheridge

2. Occipital bone

1. Basilar part

2. Condylar part

3. Squamous part

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Posterior skull basForamina

1. Internal acoustic meatusIn posterior part of temporal bone

porus acusticus

CN 7 & 8, labyrinthine artery

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Posterior skull bas2. Jugular foramen

Pars nervosa; CN9 Jacobson nerve, Inferior petPars vascularis; CN 10 & 11, Arnold nerve, jugposterior meningeal artery

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Posterior skull bas3. Groove for sigmoid sinus

In medial mastoid temporal bone

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Posterior skull bas4. Hypoglossal canal

In condylar occipital bone

CN12

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Posterior skull basForamen magnum

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Posterior skull bas

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Role of ultrasoundØ Fetal assessment

Ø Normograms of ASBL, PCFL in assof brain development

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ReferencesØ Alfred L. Weber; History of Head

Neck Radiology: Past, PresentFuture 

Ø Hansberger, Osborn et al; Diagno

and Surgical Imaging AnatomyØ N.M. Roelfsema; Three-dimensio

ultrasound study of fetal cran

anatomy International Society o