Skull & meninges Flashcards
How many bones make up the skull?
22
What are the divisions of the skull?
- Cranial vault: Space in which brain is located
- Facial skeleton: Anterior part of skull making up face
- Base: Contains the floor of the cranial cavity
What are the bones making up the cranial vault?
Unpaired:
- Ethmoid
- Frontal
- Sphenoid
- Occipital
Paired:
- Temporal
- Parietal
What are the features of the ethmoid bone?
- Cribriform plate
- Crista galli
- Perpendicular plate
- Superior/middle conchae
- Ethmoid air cells
What are the features of the frontal bone?
- Air sinuses
- Superciliary arch
- Supra-orbital notch
What are the features of the sphenoid bone?
- Greater/lesser wings
- Medial/lateral pterygoid plates
- Sella turcica
- Optic canal
- Superior orbital fissure
- Foramen rotundum
- Foramen ovale
- Foramen spinosum
What are the features of the occipital bone?
- Squamous part
- Basal part
- Hypoglossal canals
- Foramen magnum
- Occipital condyles
- Internal/external occipital protuberances
- Superior nuchal line
What are the features of the temporal bones?
- Squamous part (zygomatic process, mandibular fossa)
- Petromastoid part (middle/inner ear, internal auditory meatus, facial canal, air cells)
- Tympanic part (External auditory meatus, attachment of tympanic membrane)
- Styloid part (attachment of muscles and ligaments)
What are the features of the parietal bones?
- Contains foramina for emmisary veins connecting scalp veins to dural venous sinuses
What is the pterion?
Point on lateral aspects of the skull where several bones meet, including:
- Parietal
- Temporal
- Frontal
- Sphenoid (greater wings)
What are the 3 divisions of the cranial cavity?
- Anterior cranial fossa
- Middle cranial fossa
- Posterior cranial fossa
What are the prominent features of the anterior cranial fossa?
- Cribriform plate (of ethmoid)
- Crista galli
Which part of the brain lies within the ACF?
Frontal lobe
What are the prominent features of the middle cranial fossa?
- Sella turcica (clinoid processes + pituitary fossa)
- Foramina
What are the foramina in the middle cranial fossa?
- Superior orbital fissure
- Foramen rotundum
- Foramen ovale
- Foramen spinosum
- Foramen lacerum
(Ant. → Post.)
Which part of the brain lies within the middle cranial fossa?
Temporal lobe
What are the prominent features of the posterior cranial fossa?
- Clivus
- Internal occipital protuberance
What are the foramina in the posterior cranial fossa?
- Interal acoustic meatus
- Juglar foramen
- Foramen magnum
- Hypoglossal canal
Which part of the brain lies within the posterior cranial fossa?
- Cerebellum
- Brainstem
What are the layers of meninges?
- Pia mater
- Arachnoid mater
3 Dura mater
What are the 2 layers of dura mater?
- Endosteal layer: Intimitely associated with with the periosteum of the skull.
- Meningeal layer: Intimitely associated with the arachnoid mater.
What are the differences between cranial and spinal cord pia?
- Cranial pia is thinner than its spinal cord counterpart.
- Cranial pia is only loosely attached to surface of brain instead of tightly.
What are the differences between cranial and spinal cord arachnoid mater?
Cranial arachnoid is thicker than its spinal cord equivalent.
What are the different dural folds?
- Falx cerebri: Between 2 cerebral hemispheres
- Tentorium cerebelli: Between cerebellum and cerebral hemispheres
- Falx cerebelli: Between 2 lobes of cerebellum
- Diaphragma sella: Covers sella turcica and pituitary fossa
What are the different meningeal spaces in the cranial vault?
- Real spaces:
1. Subarachnid space: Contains CSF and arteries
2. Spinal epidural space: Contains loose connective tissue, venous plexuses and lymphatics - Potential spaces:
1. Cranial epidural space
2. Subdural space
How is the subarachnoid space formed?
- The pia mater is intimitely associated with the surface of the brain and follows into every sulcus. The arachnoid mater on the other hand, is not.
- Spaces form between 2 layers when pia follows brain into sulcus.
- Large CSF-filled spaces between 2 layers over large sulci are called cisterns.
Where does the subarachnoid space end?
Second sacral vertebrae (termination of lumbar cistern)
What are the differences between cranial dura and spinal cord dura?
Cranial dura consists of 2 layers while spinal cord dura contains only 1 (contination of meningeal layer)
Where does the dural sac and filum terminale terminate?
S2
