Osteology and Radiology of the Skull & The TMJ 2 - Cranial Floor, Fossae + Fractures Flashcards
Describe the cranial floor
- anterior, middle + posterior cranial fossae
- each fossae hold different parts of the brain
- each fossae is made of numerous bones
What bones form the anterior cranial fossa?
- frontal bone
- ethmoid bone
- lesser wings of sphenoid bone
What bones form the middle cranial floor?
-greater wings of sphenoid bone
- part of temporal bone
What bones form the posterior cranial floor?
- temporal bone
- occipital bone
What houses middle and inner ear structures?
Petrous part of temporal bone
Types of cranial vault skull fractures
- linear: fairly straight, no bone displacement
- comminuted: many fracture lines, fragments may displace inwards towards brain (depressed or not depressed)
What is the thinnest area of the skull?
Pterion
Where is the pterion located?
Point where 4 bones meet
- frontal
- parietal
- temporal
- greater wing of sphenoid bone
What is at risk of damage when the pterion is fractured?
What could this cause?
Middle meningeal artery
Extra-dural haemorrhage
What is basilar skull fractures?
Fracturing involving the bones of the cranial floor
What is periorbital ecchymosis?
What could this be a sign of?
Bruising around the eyes
Orbital plates fracture
(Anterior cranial fossa fracture)
What is a sign of a orbital plate fracture?
Bruising around eyes - perioribtal ecchymosis
What is Battle’s sign?
What is it sign of?
Bruising behind the ear
Middle cranial fossa fracture
Signs of a middle cranial fossa fracture (particularly the petrous bone)
- bleeding or fluid from ear
- Battle’s sign: bruising behind ear
- blood pooling in ear canal/drum
What is a sign of anterior cranial fossa fracture involving the ethmoid bone?
CSF rhinorrhoea - cerebrospinal fluid dripping out of nose
What is CSF rhinorrhoea?
What is it a sign of?
Fluid dripping from nose
Anterior cranial fossa fracture involving the ethmoid bone
First line imaging of basilar skull fractures
CT
Presentation of anterior cranial fossa fracture
Periorbital ecchymosis
CSF rhinorrhoea
