AEB Anatomy

What are the two groups the bones of the skull are divided into?

1. Face
2. Cranial Cavity

Define the cranial cavity.

Part of skull that houses the brain

What are the bones of the cranial cavity?

Frontal
Parietal (2)
Temporal (2)
Occipital
Ethmoid
Sphenoid

Where do the branches of the middle meningeal artery pass under?

Zygoma

Features of the temporal bone (7)

1. Squamous part
2. Petrous part
3. Mastoid Process
4. Styloid process
5. Zygomatic process
6. External acoustic meatus
7. Internal acoustic meatus

What is the zygomatic process of the temporal bone?

Anterior projection articulating with temporal process of zygoma, forming the zygomatic arch

What are the sutures present in the skull? (3)

- Coronal suture
- Sagittal suture
- Lambdoid suture

Define coronal suture

Separates frontal bone from 2 parietal bones

Define sagittal suture

Separates the 2 parietal bones

Define lambdoid suture

Separates the parietal bones from the occipital bone

What are the junctions in the skull? (3)

- Bregma
- Lambda
- Pterion

Where is the bregma located?

Between frontal and 2 parietal bones

Where is the lambda located?

Between occipital and 2 parietal bones

What is the pterion?

Lateral meeting point of frontal, temporal, parietal, sphenoid bones, also where the middle meningeal artery courses through

Features of the occipital bone (7)

- External occipital protuberance
- Internal occipital protuberance
- Clivus
- Squamous part
- External occipital crest
- Occipitomastoid suture
- Foramen magnum

Name of the suture between the two frontal bones in a neonatal skull

Metopic suture

What is the function of the fontanelle in a neonatal skull?

- Allows head to pass through vaginal canal without compressing the brain
- Closes in the first year of life

3 sections of the internal surface of the cranial cavity

1. Anterior cranial fossa
2. Middle cranial fossa
3. Posterior cranial fossa/cerebellum

What is the anterior cranial fossa demarcated by?

Lesser wing of sphenoid bone

What is the middle cranial fossa demarcated by?

Petrous part of temporal bone

Features of the sphenoid bone

1. Body/Sella turcica
a. Tuberculum sellae (elevation behind chiasmatic groove)
b. Pituitary fossa (location of pituitary gland)
c. Dorsum sellae (forms posterior wall of sella turcica)
2. Anterior and posterior clinoid processes
3. Greater and lesser wing

Features of the anterior cranial fossa

- Orbital plate of frontal bone
- Cribiform plate of ethmoid bone
- Small perforations for olfactory nerve

Features of middle cranial fossa

- Foramen rotundum
- Foramen ovale
- Foramen spinosum
- Optic canal

Features of posterial cranial fossa

- Occipital bone + foramen magnum
- Clivus lies anterior to foramen magnum
- Internal acoustic meatus
- Jugular foramen between clivus and petrous temporal bones
- Hypoglossal canal on each side of foramen magnum

Location of jugular foramen

Between clivus and petrous temporal bones

What frontal and ethmoid bones make up the floor of the cranial cavity?

F: orbital plate
E: cribiform plate

What sphenoid features make up the floor of the cranial cavity? (6)

- Body
- Lesser wing
- Anterior clinoid process
- Greater wing
- Hypophysial fossa
- Posterior clinoid process

What temporal and occipital bones make up the floor of the cranial cavity?

T: squamous and petrous parts
O: basilar part (clivus), internal occipital protuberance

3 divisions of the brain

Forebrain, midbrain, hindbrain

What does the hollow space in the neural tube develop into?

Ventricles of the brain

What does the prosencephalon become, and what division of the brain does it make up?

Telencephalon and diencephalon, forebrain

What does the rhombencephalon become, and what division of the brain does it make up?

Cerebellum and pons, and myeloencephalon, hindbrain

When do cells of the neural groove proliferate to become the neural tube?

Week 5

What does the telencephalon become?

Cerebral hemispheres (sulci and gyri)

What does the diencephalon become?

Nuclei/basal ganglia of brain, located deep to sulci and gyri

What is the brain stem made up of?

Midbrain, pons and medulla

Superolateral surfaces of the brain

Cerebrum and cerebellum

What are sulci and gyri?

Sulci are grooves, while gyri are bumps between sulci

3 important sulci and locations

1. Central sulcus: divides frontal lobe from parietal lobe
2. Lateral sulcus: divides temporal lobe from frontal and parietal lobes
3. Parietooccipital sulcus: between parietal and occipital lobes

Lobes of cerebral cortex (7)

Frontal, parietal, temporal, occipital lobes
Insula, limbic, uncus lobes

What does the limbic lobe control?

Emotions and memory

What does the uncus lobe control?

Olfactory senses

Features of a horizontal section of the cerebrum (6)

- Cerebral cortex
- White matter
- Deep grey matter
- Corpus callosum
- Thalamus
- Lateral ventricle

Definition of cerebral cortex

Outermost layer of gray matter
Surface area highly folded into sulci and gyri

Definition of white matter

Groups of myelinated axons that connect to other regions or the spinal cord

Definition of deep grey matter

Collection of neuron cell bodies lying within the nervous system

Name the meninges (3)

1a. Dura: periosteal layer
1b. Dura: meningeal layer
2. Arachnoid mater
3. Pia mater

Which layer of meninges dips into the sulci and gyri?

Pia mater

What does the subarachnoid space contain?

Cerebrospinal fluid that flows from ventricles, and blood vessels

Where is the periosteal layer of the dura attached to?

Inner surface of the cranial cavity

What does the dural venous sinus contain?

Venous blood

Dura partitions

Falx cerebri, tentorium cerebelli, falx cerebelli, and diaphragma sellae