Space-occupying Lesions Flashcards
5 layers of the scalp
(SCALP)
Skin
Connective tissue
Aponeurosis
Loose connective tissue
Pericranium
In which scalp layer is the rich anastomotic layer located?
Connective tissue
(therefore lacerations and incisions bleed excessively)
Know bones + sutures + processes of skull
Where is the pterion?
And what is its clinical significance?
Thinnest part of skull
therefore fractures easiest
Middle mengingeal artery courses over deep aspect of the pterion, excessive bleeding when ruptured
What do meninges protect?
Brain and spinal cord.
They’re basically continuous membranes
(meningitis)
3 layers of meninges?
(+ 1 space)
Dura mater - hard, sensory supply from CN V, adherent to internal aspect of the skull
Arachnoid mater - arachnoid granulations which reabsorb CSF)
Subarachnoid space (containing circulating CSF)
Pia mater - adherent to the brain + the blood vessels and nerves entering and leaving the brain
What meningeal layer is the tentorium cerebelli?
Sheet of DURA MATER ‘tenting’ over the cerebellum
(with a central gap to allow brainstem to pass through)
Danger triangle of face - why is it dangerous?
Infection easily transmitted into the cranial cavity
Label
Where is CSF produced ?
Choroid plexus
(located in the lateral and third ventricles)
How to access CSF for testing?
L3/4 or L4/5
Below spinal cord (reduce risk) and still has a subarachnoid space until S2
Where is CSF reabsorbed?
From subarachnoid space via arachnoid granulations of the arachnoid mater
Where can a supratentorial herniation occur?
Subfalcine (below the falx cerebri)
Central
Uncal/transtentorial
Transcalvarial
Where does infratentorial herniation occur?
Upwards
Downwards/tonsillar herniation
(cerebellar tonsils herniate into the foramen magnum)
