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Anatomy 1 > Skull > Flashcards

Flashcards in Skull Deck (25):

The skull base forms ...

the floor of the cranial cavity, separates the brain from the other facial structures, its a complex anatomical region


The 3 parts of the skull base are ...

Endocranial (inner) skull base, Skull Base Foramina, Extracranial (outer) skull base


Describe the Endocranial (inner) skull base

the inner surface of the skull, consists of the cranial cavity on which the brain rests


The 4 types of bone forming the skull base are ...

Frontal bone, Sphenoid bone, Temporal bone, Occipital bone


Anatomically, the inner surface of the skull base is formed by ...

The anterior cranial fossa, middle cranial fossa, posterior cranial fossa


Describe the anterior cranial fossa - limits - 2 points

it's limited anteriorly by frontal bone & by the posterior wall of the frontal sinus, limited posteriorly by the margin of the lesser wing of sphenoid bone


What is the anterior cranial fossa formed by

ethmoid bone, sphenoid bone, frontal bone


Describe what the lateral part of the anterior cranial fossa forms and what the median (central) part of the anterior cranial fossa is formed by

lateral part = form the roof of the orbits
median (central) part = formed by crista galli, the cribriform plate of the ethmoid plane and the sphenoid bone


Describe the middle cranial fossa - formed by, limits - 3 points

formed by sphenoid and temporal bones, limited anteriorly by the lesser wings of the sphenoid bones, limited posteriorly by petrous bones


Describe the posterior cranial fossa - formed by, limits - 3 points

formed by occipital bones, limited anteriorly by posterior walls of petrous bones, limited posteriorly by grooves of transverse sinuses


Describe skull base foramina - 2 points

these are the several foramina which are in the bones of the skull base, nerves/arteries/veins pass through them


Skull Base Foramina in the Ethmoid Bone

olfactory foramina


Skull Base Foramina in Sphenoid Bone

optic canal, superior orbital fissure, foramen rotundum, foramen ovale, foramen spinosum, foramen lacerum


Skull Base Foramina in Temporal Bone

internal acoustic meatus, jugular foramen


Skull Base Foramina in Occipital Bone

hypoglossal canal, foramen magnum


Describe the what forms the anterior part of the extracranial skull base

Zygomatic bone, Maxillary bone, Palatine bones


Describe the remainder of what forms the extracranial skull base

Occipital bones, temporal bones, sphenoid bones


Describe skull base fractures etc - 5 points

skull base fractures are of high importance in neurotrauma, often associated with cranial vault, mid face fractures occur in head injuries and are often related to brain injuries, involvement of nerves passing through a foramen in a respective region should always be considered, CT = gold standard for detecting these fractures


What are the %'s of fractures which have occurred in various places

70% occur in anterior fossa
20% occur in the middle central skull base
5% occur in the middle or posterior fossa


Clinical Signs - Battle's Sign

bruising over the mastoid sinus (just behind auricle), delayed physical finding associated with base of skull fractures


Clinical Signs - Hemotympanum =

blood behind ear drum, "racoon eyes" (periorbital bruising), other delayed findings


Examples of what you should look for when keeping general close observations to ensure no late sequela

Delayed CSF leak - most relevant clinical sign, neurological symptoms - if deterioration then surgery may be considered


monitoring must include ... - 2 points

close clinical observation with regular neurological checks, re-scan


Describe CSF leak

where cerebrospinal fluid leaks through the mouth/nose due to a tear in dura mater related to a traumatic brain injury, requires surgical intervention


Surgical approaches to remove tumours from skull

range from traditional neurosurgery to minimally invasive endonasal/endoscopic surgery