Skull & Cranial Cavity Flashcards
What are the 5 layers of the SCALP?
Skin Connective tissue Aponeurotic layer Loose connective tissue Pericranium
What is the innervation of the scalp?
Trigeminal nerve (CN 5) and spinal cutaneous nerves
Name the 8 neurocranial bones
Occipital 2 Temporal 2 Parietal Sphenoid Ethmoid Frontal
Name the 14 viscerocranium bones
2 nasal conchae 2 nasal bones 2 maxilla 2 plantine 2 zygomatic 2 lacrimal vomer mandible
Name the 3 layers of the meninges
Dura Mater
Arachnoid Mater
Pia Mater
What are the 2 layers of the dura mater?
Endosteal layer- stuck to skull, lines skull only, stops at magnum foramen
Meningeal layer- around brain and spinal cord
layers are closely applied unless forming a dural sinus
Nerve supply of dura mater?
CN 5, 10
C1-3
Sympathetic
Blood supply of dura mater?
Middle meningeal artery
What is the function of the meningeal layer of the dura?
Creates series of folds/septa dividing the cranial cavity, prevents/restricts movement.
What does the Falx Cerebri separate?
Cerebral hemispheres
What does the Tentori Cerebelli separate?
Cerebral hemispheres from cerebellar hemispheres
What does the Falx Cerebelli separate?
Cerebellar hemispheres
What are 3 clinical applications of the dura mater?
Dura stretching is anatomical basis of headache
Damage to middle meningeal artery - extradural haematoma
Tentorial herniation- caused by space occupying lesion causing herniation of the temporal lobe
Describe the arachnoid mater
Middle layer of meninges
Loosely applied
avascular
All structures passing to/from brain pass through subarachnoid space
What meninges contains the CSF?
The arachnoid mater within the subarachnoid space
What produces CSF?
Choroid plexus in the brain ventricles - around 500ml produced per day
What is the function of CSF?
Provides buoyancy to brain protecting it from mechanical forces
What is the function of arachnoid granulations?
To affect the transfer of CSF to the venous sinuses to prevent buildup of CSF in subarachnoid space
Describe the Pia mater
Innermost layer of meninges
delicate vascular membrane
close to brain following gyri and sulci
cerebral arteries enter brain carrying sheath of pia mater with them to create periarterial space
what are the 3 layers of the spinal cord meninges and how does this differ to the brain?
- dura mater- with meningeal layer only
- arachnoid mater
- pia mater
What is leptomeningitis?
Infection and inflammation in arachnoid and pia maters. May enter subarachnoid space and enter blood causing septicaemia
What are dural sinuses?
spaces created by layers of dura mater. Drain blood and CSF via cerebral veins.
Where do the dural sinuses drain into?
Jugular vein
What are the features of dural sinuses?
Thick walled endothelium
No valves
No smooth muscle
What are the 2 main arteries supplying blood to the brain?
Internal carotid artery
Vertebral artery
What are the 2 terminal branches inside the skull?
Anterior cerebral artery
Middle cerebral artery
Which artery do the vertebral arteries unite to form?
Basilar artery
What is the cerebral arterial circle formed from?
Anastomosis between 2 internal carotid arteries and 2 vertebral arteries
What areas of the brain do the cerebral arteries supply?
Anterior cerebral artery: medial and superior surfaces & frontal pole
Middle cerebral artery: lateral surfaces and temporal pole
Posterior cerebral artery: inferior surfaces and occipital pole
What causes a stroke and why?
Embolism in a cerebral artery because there is no anastomosis of cerebral arteries once inside the brain so causes neurological deficit
When does mixing in posterior communicating artery occur?
Only when ICA or vertebral artery is occluded- in this case blood passes back and forth across the PCA to compensate for reduced blood flow
Which cranial nerves pass through the cribiform plate
CN 1
Which cranial nerves pass through the optic canal?
CN 2, Opthalmic A
Which cranial nerves pass through the superior orbital fissure?
CN 3,4,6,5 V1
Which cranial nerves pass through rotundum
CN 5 V2
Which cranial nerves pass through ovale?
CN 5 V3
Which structures pass through spinosum?
Middle meningeal artery
Which structures pass through lacerum?
Carotid artery traverses it (doesn’t pass through)
Which cranial nerves pass through internal acoustic meatus?
CN 7 and 8
Which cranial nerves pass through jugular foramen?
CN 9,10,11, IJV
Which cranial nerves pass through hypoglossal canal?
CN12
Which structure passes through the foramen magnum?
Spinal cord
