T1 L2 Skull & cranial cavity Flashcards
What are the 5 layers of the scalp?
Skin Connective tissue (dense) Aponeurotic layer Loose connective tissue Pericranium
What nerves innervate the scalp?
Trigeminal nerves
Spinal cutaneous nerves
What are the 2 sections of the skull?
Neurocranium
Viscerocranium
How many bones are in the neurocranium?
8
What are the bones making up the neurocranium?
Occipital Temporal x 2 Parietal x 2 Sphenoid Ethmoid Frontal
What are the bones making up the viscerocranium?
Nasal conchae x 2 Nasal bones x 2 Maxilla x 2 Palatine x 2 Zygomatic x 2 Lacrimal x 2 Vomer Mandible
What is the role of the foramina?
Permits nerves & blood vessels to enter of exit cranial cavity
What is the base of the skull divided into?
Anterior cranial fossa
Middle cranial fossa
Posterior cranial fossa
Give some examples of foramina
Cribiform plate Optic canal Superior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum Internal acoustic meatus Stylomastoid foramen Foramen lacerum Jugular foramen Hypoglossal canal Foramen magnum
What are the 3 meninges layers?
Dura mater
Arachnoid mater
Pia mater
What is the role of the meninges?
Protection
Support network for blood vessels
Forms a fluid-filled cavity to cushion & nourish the brain
What are the 2 layers of dura mater?
Endosteal layer
Meningeal layer
Where is the meningeal layer found?
Around the brain & spinal cord
Where is the endosteal layer found?
Only lines the skull
What is the nerve supply to the dura mater?
Cranial nerve V
Cranial nerve X
C1-3
Sympathetic
What is the blood supply to the dura mater?
Middle meningeal artery
What is the purpose of folds in the meningeal dura mater?
Prevent / restrict movement of the brain
What does the falx cerebri separate?
Cerebral hemispheres
What does the tentorium cerebelli separate?
Cerebellar hemispheres from cerebral hemispheres
What does the falx cerebelli separate?
Cerebellar hemispheres
What is the anatomical basis of a headache?
The dura is sensitive to stretching
What can lead to an extradural (epidural) haematoma?
Damage to the middle meningeal artery
What causes a tentorial herniation?
A space occupying lesion causing herniation of the temporal lobe
Which meningeal layer is avascular?
Arachnoid mater
Describe the arachnoid mater
Thin avascular layer
Loosely applied with projections
Where is the CSF found in the subarachnoid space produced?
By choroid plexus in brain ventricles
What is the aim of the CSF?
It provides buoyancy to the brain to protect it from mechanical forces such as a blow to the skull
Describe the Pia mater
Very delicate vascular membrane
Gives brain a shiny coating
The cerebral arteries enter the brain carrying a sheath of Pia mater with them
What is leptomeningitis?
Infection & inflammation in the arachnoid & Pia mater
Infection may enter the subarachnoid space & into the blood = septicaemia
What are dural sinuses?
Sinuses that sit between the dural folds
Contain drained blood & CSF from the brain via cerebral veins
Describe the properties of the dural sinus
Thick walled endothelium
No valves
No smooth muscles
What do the dural sinuses drain into?
The internal jugular vein
What are the 2 main arteries supplying the brain?
The internal carotid artery
Vertebral artery
What are the 2 terminal branches inside the skull?
The anterior cerebral artery
The middle cerebral artery
What happens to the vertebral arteries?
They pass within the cervical vertebrae and enter the foramen magnum where they unite to form the basilar artery.
What forms the circle of Willis?
Anastomoses of the 2 internal carotid & 2 vertebral arteries
What does the anterior cerebral artery supply?
The medial & superior surfaces of the brain & frontal pole
What does the middle cerebral artery supply?
The lateral surfaces & temporal pole
What does the posterior cerebral artery supply?
The inferior surfaces & occipital pole
Which layer of the meninges is avascular & loosely applied?
The arachnoid layer
