Neuroanatomy - Scalp, Skull, Cranial Cavity Flashcards
What are the 5 parts of the scalp
Skin (Epidermis & Dermis)
Connective Tissue (Hypodermis, contains nerves and arteries)
Aponeurosis (runs from anterior and posterior Temporalis muscles)
Loose connective tissue (allows the scalp to move on top of the skull)
Pericranium (periostium)
Describe the set up for the superficial veins, diploic, and Emissary veins.
What is the clinical correlation with these?
The superficial veins rest on top of the bone in the connective tissue.
The Emissary veins can take blood from the superficial veins through the scalp into Venous Dural Sinuses where they can drain back into the internal jugular veins.
As the emissary veins pass through the bone, there are Diploic Veins sandwiched within the bone.
Clinical: None of these veins have valves so blood can go in any direction, including infections. Normally blood is flowing from inside out but if you are infected in the scalp it can flow back into the meninges –> Meningitis.
Where is the Superficial temporal artery?
What is it a branch of?
It is located just anterior to the ear
It is a branch of the external carotid artery
What nerve acompanies the superficial temporal artery?
What is the temporal fascia?
Auriculotemporal nerve (auriculo = ear):
- Branch of the mandibular division of the CN V
- This is a sensory nerve (just runs into the skin)
- Ends in the temporal fascia
Temporal Fascia: Covers the temporalis muscle
What two layers of the meninges make up the dura mater?
What is contained in the Dura?
What are the arachnoid granulations and what do they do?
The Periosteal layer is the outermost. Underneath is the Meningeal layer and is connected to the Periosteal layer.
Inside the dura are the meningeal arteries and Arachnoid granulations: These filter the CSF and reintroduces it to the fluid pool by pushing it into the Dural Venous Sinus and all the blood.
What supplies the temporal bone and meninges?
Where does it come from?
The Middle Meningeal artery supplies the temporal side of the skull and the meninges.
It is a branch of the maxillary artery and comes in through the foramen spinosum.
Dural Venous Sinuses
-Where is the superior sagittal sinus?
What are Arachnoid granulations?
What is the medical term for the Lacunae lakes?
-The Superior Sagittal Sinus is a trench made up by a split in the periosteal and meningeal dura
The arachnoid granulations/villi are important for transferring CSF to the veins so that it can be reintroduced into the sysytem.
Lateral venous lacunae
Meningitis can result in a dural clotting –> blockage of blood from draining.
What is the Falx Cerebri?
What is the Falx Cerebelli?
Periosteal layer of the derma is always attached to the bone
The meningeal layer splits off to make the meningeal sinus
Eventually the meningeal layer goes deep and makes a septum called teh Falx Cerebri that seperates the two halves of the brain.
The Falx Cerebelli is the same thing but located under the Confluence of the Sinuses where all the different sinuses meet up and move into the transverse sinus.
Where are cerebral veins found?
What do all the sinuses drain into?
What foramen do they use for this?
Cerebral veins run along the pia of the brain but penetrate throught the arachnoid membrane, pierce through the meningeal layer of the dura, and drain into the dural sinus (Ex. Saggital sinus or transverse sinus, etc.)
All the cerebral veins drain into lacunae and sinuses that then drain into the confluence of the sinuses –> transverse sinuses –> sigoid sinus –> internal jugular veins
The jugular veins run throught the jugular foramen
What does the Falx Cerebri attach to?
The crista galli in the front all the way to the tentorium cerebelli (tent of the cerebrum)
What is under the Dura?
The arachnoid membrane lies under the dura covering the brain.
The Pia is under the arachnoid membrane and attaches directly to the brain.
Inbetween the arachnoid membrane and the pia is a subarachnoid space.
Where is the Falx cerebelli?
Why is the tentorium cerebelli important?
The TC is a landmark. Above it is the Supratentorial region holding the cerebrum and diencephalon. Underneath is the Cerbellum and brain stem.
Describe an Epidural hemorrhage
A meningeal artery ruptures and blood pools between the bone and the periosteal dura.
- It forms a lens shape that is pushing the brain inward,
- This forms an epideural space (it did not exist before the muchkil)
- This is life threatening
What is a Subdural hemorrhage?
This is the pooling of blood between the dura and the arachnoid space via a ruptured cerebral vein.
- This is less likely to occur as a child because the dura is softer.
- This is bleeding into the brain
- When you look at it on a CT-scan it looks like an even accumulation and is not lens-like.
What is a subarachnoid hemorrhage?
One of the cerebral arteries has ruptured and you now have bleeding into the subarachnoid space.
-A spinal tap can show whether it is a subarachnoid hemorrhage by having blood in the CSF.
Name the cranial nerves and associated numbers.
Be sure to check the power point
http://www.olicognography.org/drawings/cranial%20nerves.jpg
I. Olfactory
II Optic
III Oculomotor
IV Trochlear
V Trigeminal
VI Abducens
VII Facial
VIII Vestibulocochlear
IX Glossopharyngeal
X Vagus
XI Accessor
XII Hypoglossal
Describe the Olfactory nerve and look at the power point slide 56
The nerve runs from inside the top of the nose, through the cribiform plate, into the Olfactory bulb.
-The olfactory bulb is extended out and what you are seeing in the brain. Remember that this is the olfactory tract not the nerve.
Locate the:
- Optic nerve
- Oculomotor
- Trigeminal nerve ganglions (what sort of nerve cell are these?)
- Trochlear
- Trigeminal
- Abducens
- Facial
-
See Power point slides 57 and 60
Important sinuses you should know
- Superior Sagittal sinus
- Confluence of the sinuses
+ contains occiptal sinus, straight sinus, and sagitall sinus
- The confluence pools into the transverse sinus and sigmoid sinus (goes into the jugular vein)
- The great cerebral vein drains into the straight sinus and drains the deeper veins of the brain.
Clnical: Dural venous sinus and internal vertebral plexus both have no valves so any bacteria or cancer can spread throughout the whole CNS if it gets inside.
What makes up the trigeminal ganglion?
What makes up the Dural Venous Sinus?
- Opthalmic (V1), Maxillary (V2), Mandibular (V3)
+ These leave throught the superior orbital fissure, the foramen rotundem, and the foramen ovale respectively
-The Dural venous sinus is found in the cavernous sinus which are connected by the intercavernous sinus. This allows easy distribution of chemicals into the blood by the pituitary gland.
What artery and nerves run throught the Cavernous Sinus? See slide 62 of the power point
What nerves are located in the wall of the cavernous sinus?
- Artery of cavernous sinus: Internal carotid artery (if you have an embolism, the first thing to go will be your eye sight because it is being supplied by the internal carotid artery)
- Nerve of cavernous sinus: Abducens
In the wall of ther cavernous sinus
Nerves: Oculomotor, Trochlear, Ophthalmic (V1), Maxillary (V2)
