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
