Extradural haemorrhage Flashcards
Name the different types of herniation that can occur in the brain.
- Subfalcine
- Tonsillar
- Uncal
- Central supratentorial
What is subfalcine herniation, and what does it compress?
The brain tissue herniates under falx cerebri and crosses midline. It compresses ACA leading to frontal and parietal lobe deficits.
What is central supratentorial herniation and what does it compress?
Supratentorial brain tissue presses into infratentorial compartment. It compresses CN3, pituitary stalk (diabetes insipidus), pontine artery tearing.
What is uncal herniation and what does it compress?
The temporal lobe displaces into the infratentorial compartment. It squishes CN3, reticular formation and cerebral peduncles.
What is function of reticular formation?
It is a portion of the brain located in the brainstem central core. It passes through medulla, pons and stops midbrain. It regulates function in motor control, sensory control, visceral control and control of consciousness (sleep and alertness).
What is tonsillar herniation and what does it compress?
Tonsillar herniation is cerebral tonsils displacing into foramen magnum. It compresses cardiorespiratory centres in the medulla and leads to death.
What is Cushing syndrome?
Triad of symptoms observed in ongoing raised ICP:
- HTN
- Bradycardia
- Irregular breathing
What is the pterion?
It’s an area where bone plates forming the skull fuse together:
- Frontal
- Sphenoid
- Parietal
- Temporal
What arteries are epidural haemorrhages associated with?
Tearing of the middle meningeal arteries.
What vessels are subdural haemorrhages associated with?
Tearing of the cortical veins.
Briefly describe the pathway of oculomotor nerve.
It lies in the midbrain, near superior colliculi. It contains motor supply and parasympathetic supply to the eye muscles.
It arises from the interpeduncular fossa, travels between PCA and SCA. It pierces arachnoid and dura mater of the roof of cavernous sinus behind ICA.
It travels downwards along lateral wall of cavernous above abducens nerve.
Superior branch: superior rectus and levator palpabrae superioris. Inferior branch (parasympathetic runs with it): medial rectus, inferior rectus, inferior oblique.
Briefly describe pathway of trochlea nerve.
Trochlea nucleus lies midbrain at level of inferior colliculus.
Decussate completely dorsal to aqueduct, before emerging dorsally near midline behind inferior colliculus.
It runs along free edge of tentorium cerebelli, directed to the roof o the cavernous sinus, piercing arachnoid and dura mater.
Runs lateral wall of the cavernous sinus. Crossed medially by CN3. Enters superior orbital fissure lateral to the tendinous ring, passes over levator palpebrae superioris to enter superior oblique.
What are the different anatomical correlations of medulla with respiratory functions?
Dorsal respiratory group = inspiration control.
Ventral respiratory group = expiration
Pneumotaxic centre = rate and depth of breathing
Apneustic centre = stimulatory impulses to inspiratory centre
What sign do you get with compression of trochlea nerve?
Inability to move the eye down and out.
Describe the pathway of abducens nerve.
It emerges at the base of pons, above pyramid of medulla. Turns upwards between AICA and pons.
Runs between two layers of the dura, entering inferior petrosal sinus at the apex of petrous temporal bone, and it enters the cavernous sinus.
Enters tendinous ring below inferior division of CN3 and enters lateral rectus muscle.
