Intracranial Region Flashcards
Cranial fossae
- 3 of them
- Anterior
- Middle
- Posterior
Anterior Cranial Fossa
- Contains the FRONTAL LOBE
Includes:-
- Frontal bone
- Ethmoid
- Lesser wing of Sphenoid
Middle Cranial Fossa
- Contains the TEMPORAL LOBE
Includes:-
- Sphenoid (greater wings and body plus sinus)
- Petrous part of the temporal bone
Posterior Cranial Fossa
- Contains the CEREBELLUM
Includes:-
- Temporal bone
- Occipital bone
Sella Turcica
“Turkish Saddle”
Saddle like prominence crossing the midline on the superior surface of the body of the sphenoid
Contains the PITUITARY GLAND
Cribiform plate
Structures passing through:
CN I - Olfactory Nerve
Optic Canal
Structures passing through:
- CN II: Optic Nerve
- Opthalmic Artery
Foramen Cecum
Structures passing through:
- Emissiary veins to the nasal cavity
Superior Orbital Fossa
SOF
Structures passing through:
- Cranial nerves:
CN III - Occulomotor
CN IV - Trochlear
CN V1 - Opthalmic branch of trigeminal
CN VI - Abducens
- Opthalmic veinsForamen Ovale
Structures passing through:
- CN V3 - Mandibular branch of the trigeminal
- lesser petrosal nerve
Foramen Rotundum
Structures passing through:
- CN V2 - Maxillary branch of the trigeminal
Foranen Spinosum
Structures passing through:
- MIDDLE MENINGEAL ARTERY
Petrosal nerves:
- Greater
- Lesser
Greater travels through:
- Hiatus for the greater petrosal n.
Lesser travels through:
- Hiatus for the lesser petrosal n.
Foramen Magnum
Structures passing through:
- End of brainstem/beginning of SPINAL CORD
- Vertebral Arteries
- Spinal roots of the accessory nerve (CN XI)
- Meninges
- Medulla Oblongata
Internal Acoustic Meatus (IAM)
Structures passing through:
- Labyrinthine Artery
Jugular Foramen
Structures passing through:
- Inferior petrosal sinus
- Sigmoidal sinus (forming the Internal Jugular Vein)
Hypoglossal canal
Structures passing through::
- Meningeal branch of the Ascending Pharyngeal Artery
Condylar Canal
Structures passing through:
- Emissary Vein
Trigeminal Nerve - CN V
Made up of 3 branchs
Largest Cranial Nerve
CN V1 - Opthalmic branch (purely SENSORY)
CN V2 - Maxillary branch (purely SENSORY)
CN V3 - Mandibular nerve (SENSORY & MOTOR function)
Meninges
- Made of 3 layers
- Dura Mater (tough)
- Arachnoid Mater
- Pia Mater
Choroid Plexus
- Function
Makes CSF
Dura Mater
- tough
- has 2 layers
Outermost of the meninges Made of COLLAGEN FIBRES Acts as a mechanically protective covering 2 layers: - Periosteal layer - Meningeal layer
Arachnoid Mater
Delicate - small veins run between Dura and Arachnoid
Made of NON-VASCULAR CONNECTIVE TISSUE
Pia Mater
Continuous with the surface of the brain/cord
Supports the blood supply of the brain
Forms the Choroid plexus together with ependymal cells
CAN’T be seen with the naked eye
Middle Meningeal Artery
- Rupture: can cause an Extradural/Epidural Haemorrhage
Largest of the 3 paired arteries supplying the meninges.
Branch of the MAXILLARY ARTERY; a terminal branch of the EXTERNAL CAROTID ARTERY
Runs through the Foramen Spinosum to supply the Dura Mater and the Calvaria
Runs beneath the Pterion, where the skull is very thin
Falx Cerebri
Fold of Dura Mater in the longitudinal fissure that separates the cerebral hemispheres
Falx Cerebelli
Fold of the Dura Mater that separates the Cerebellar hemispheres
Tentorium Cerebelli
Extension of the Dura Mater separating the cerebellum from the inferior portion of the Occipital lobes
Dural Venous Sinuses
Spaces between Periosteal and Meningeal layers of dura containing venous blood.
No valves in the venous sinuses
Blood in the venous sinuses originates mostly from the Brain and Cranial cavity
Drains via the Internal Jugular Vein
Dural venous sinuses
- Superior sagittal sinus
- Inferior sagittal sinus
- Straight sinus
- Cavernous
- Sup & inf petrosal
- Transverse & sigmoid sinuses
Contents of Cavernous Sinus
- Carotid Artery
- Cranial nerves:
Occulomotor; Trochlear; Opthalmic; Maxillary; Abducens - Pituitary gland
- Sympathetic nerve
Extradural/ Epidural Haemorrhage
- Location
- Commonly occurs due to
Occurs between the Dura and the Skull
Common following a blow to the side of the head
Often due to the rupture of the Middle Meningeal Artery
Middle Meningeal artery
3rd branch of the first part (retromandibular part) of the Maxillary Artery
Which is one of the two terminal branches of the External Carotid Artery
Subdural Haemorrhage
Occurs when veins crossing the subdural space bursts.
Blood builds up between the dura mater and the arachnoid.
Life threatening; blood may compress the brain
Leads to:-
- Loss of consciousness
- Paralysis
- Death
Can be ACUTE or CHRONIC
Subarachnoid Haemorrhage
Occurs between the Arachnoid and the Pia Mater
CSF circultion
Formed in the Ventricles from the Choroid Plexus
Exits from the vent sys. via openings in roof of 4th ventricle into sub-arachnoid space (Cisterna Magna)
Re-absorbed via Arachnoid Granulations into systemic veins (e.g. sup sagittal sinus)
Spinal cord meninges
- from outside to inside
- Dura Mater
- Arachnoid
- Pia Mater
then white & grey matter
