Session 1: Cranium, Meninges and Brain Flashcards by Georgia Leggett

What are the 2 parts of the cranium?

Neurocranium (Vault)

Viscerocranium (Facial skeleton)

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Name all the cranial bones.

Frontal
Parietal x2
Temporal x2
Occipital
Sphenoid
Ethmoid

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Name all the facial bones.

Mandible (jaw bone)
Maxilla x 2 (above teeth)
Zygomatic x 2 (cheekbones)
Nasal x 2
Lacrimal x 2 (in orbit, related to drainage of lacrimal glands in top corners of eyes)
Inferior Nasal Conchae x 2 
Vomer (in middle of skull)
Palatine x 2 (top of mouth)

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What are the gaps between the bones in the skull during development called?

Fontanelles

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What is the shape of the sphenoid bone and what its 2 parts?

Butterfly shaped

Greater + Lesser wing

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What is another name for the conchae and what is their role?

Turbinate Bones

increase SA of the upper respiratory tract

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What are the tough fibrous joints between bones in the skull called?

Sutures

Permit little or no movement

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Give an example of a synovial joint within the skull.

Temporo-mandibular Joint

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Give the names of the sutures between a) frontal and parietal bones, b) parietal bones and c) parietal and occipital bone.

Coronal Suture
Sagittal Suture
Lambdoid Suture

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What is the name given to the point at which the sagittal suture meets the coronal suture?

Bregma

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What is the name given to the point at which the sagittal suture meets the lambdoid suture?

Lambda

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What are the 3 parts of the ethmoid bone?

Orbital Plate
Middle Nasal Concha
Perpendicular Plate

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What is the name of the hole in the mandible through which a branch of the inferior alveolar nerve and vessels pass?

Mental Foramen

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What are the 2 foramina found above and below the orbit?

Supraorbital Foramen

Infraorbital Foramen

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What is the name of the midline notch just below the nose?

Anterior Nasal Spine

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Which bones form the medial part of the orbit?

Orbital plate of ethmoid
Frontal process of maxilla
Lesser wing of sphenoid
Lacrimal

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What part of the mandible advances towards the tempero-mandibular joint?

Ramus

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What is the name of the flat part of the occipital bone?

Squamous part

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What is the name of the suture between the occipital and temporal bones?

Occipitomastoid Suture

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What are the 2 horizontal ridges found on the occipital bone?

Superior + Inferior Nuchal Lines

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What is the midline protrusion of the occipital bone called?

External Occipital Protuberance

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What is the name given to the highest point of the protrusion of the occipital bone?

Inion

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Name the ridge that goes from the external occipital protuberance down to the foramen magnum

External Occipital Crest

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How can the cranial base be divided?

Anterior cranial fossa: contains frontal lobe
Middle cranial fossa: contains temporal lobe
Posterior cranial fossa: contains cerebellum

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Which layer of the meninges goes in and out of the sulci?

Pia Mater

What are the 2 layers of dura in the cranium?

Periosteal (closest to skull) | Meningeal (closest to brain)

What difference between the cranial dura and spinal dura allows for an epidural space?

At the foramen magnum the dura goes from having 2 layers (periosteal + meningeal) to just 1 layer (equivalent of the meningeal layer). Thus, there is an epidural space.

What drains into the venous blood filled spaces between dural layers?

CSF via the arachnoid villi

Describe the arrangement of dural venous sinuses and the direction of blood flow.

A separation between dural layers at top of falx = superior sagittal sinus. Another separation at bottom of falx= inferior sagittal sinus. This drains into the straight sinus, which joins the superior sagittal sinus + the 2 transverse sinuses at the confluence of sinuses. Blood drains to the confluence of sinuses, then along the transverse sinuses to the sigmoid sinus, which then forms the internal jugular vein.

What flat sheet of dura (with a small hole in it) keeps the pituitary gland in the sella turcica?

Diaphragma sellae

List 3 different types of brain herniation and their consequences.

Subfalcine: part of the frontal lobe goes under the falx cerebri (not usually clinically significant) Uncal: medial part of the temporal lobe goes under the tentorium cerebelli – affects the midbrain, can cause unconsciousness Tonsilar: cerebellar tonsils go through foramen magnum. Affects the medulla + causes cardiorespiratory failure

Which 2 main vessels supply the circle of Willis?

Vertebral arteries | Internal carotid arteries

There is a weak point in the skull behind which you find the largest artery entering the skull. Name the part of the skull in question and the artery.

Pterion | Middle meningeal artery

What is the clinical relevance of the location of the middle meningeal artery and the Pterion?

This is a possible site for extradural haemorrhage

Which veins drain into the cavernous sinus?

Superior + inferior ophthalmic veins | There is also communication with the pterygoid plexus

Which vein is joined to the end of the straight sinus at the point where the inferior sagittal sinus joins the straight sinus?

Great cerebral vein

What is the pterygoid plexus?

A venous plexus, situated between the temporalis muscle + lateral pterygoid muscle, + partly between the 2 pterygoid muscles

Which sinus connects the 2 inferior petrosal sinuses?

Basilar Sinus

Name 3 structures found within the cavernous sinus. Which cranial nerves travel through the lateral walls of the cavernous sinus?

Internal carotid artery Abducens nerve Pituitary Gland Lateral walls: occulomotor, trochlear, trigeminal (ophthalmic + maxillary divisions)

What is the structure that separates the 2 lateral ventricles?

Septum pellucidum

What structure contains the main fibre tracts going up and down from the cortex?

Internal capsule

What structure is medial to the posterior limb of the internal capsule in a brain cut in the transverse plane?

Thalamus

What are the 5 different tissue layers of the scalp?

``` Skin Connective Tissue Aponeurosis Loose Areolar Tissue Periosteum ```

What type of intracranial haemorrhage is associated with damage to the middle meningeal artery?

Epidural Haemorrhage | AKA. Extradural haemorrhage

What is the tentorial notch and what is its clinical significance?

A triangular opening in the tentorium cerebelli through which the brainstem extends from the posterior to the middle cranial fossa. In increased intracranial pressure, part of the temporal lobe could be pushed through this opening.

Which major arteries pass through the foramen magnum?

Vertebral arteries

List all the cranial nerves and the foramina through which they pass

Olfactory (I): Cribiform Plate Optic (II): Optic Canal Oculomotor (III), Trochlear (IV), Trigeminal (ophthalmic – V1) + Abducens (VI): Superior Orbital Fissure Facial (VII) + Vestibulocochlear (VIII): Internal Acoustic Meatus Glossopharyngeal (IX), Vagus (X) + Accessory (XI): Jugular Foramen Hypoglossal (XII): Hypoglossal Canal

List the 3 branches of the trigeminal nerve and the foramina through which they pass

Ophthalmic: Superior Orbital Fissure Maxillary: Foramen Rotundum Mandibular: Foramen Ovale

Which vessel passes through the optic canal?

Ophthalmic Artery

Which vessel passes through the superior orbital fissure?

Superior Ophthalmic Vein | Inferior Ophthalmic Vein (branch of)

Which foramen does the middle meningeal artery and vein pass through?

Foramen Spinosum

Which foramen does the internal carotid artery pass through?

Carotid Canal

Which vessel passes through the internal acoustic meatus?

Labyrinthine Artery

Which vessel passes through the jugular foramen?

Sigmoid Sinus --> Internal Jugular Vein

Which foramen do the spinal roots of the accessory nerve pass through?

Foramen Magnum

How many bones is the skull comprised of?

22 bones (excluding ossicles of ear)

What are cranial fosse?

Parts of the skull base in which areas of the brain are seated

What are skull foramina?

Entry + exit holes

What are dural sinuses?

Sites where blood drains back into systemic circulation

Why are babies born with unfused skull bones?

Skull bones need to move as the baby comes out of the birth canal

What are the occipital condyles?

The points where the occipital bone joins to C1 vertebra | "Yes joint"- allow head to move back + forth

What part of the mandible protrudes under the zygomatic bone?

Coronoid Process

Where is CSF reabsorbed?

Arachnoid granulations