AEB - Anatomy

Cranial bones

bones of the skull that enclose and protect the brain and meninges, meeting at sutures (immovable fibrous joints).

Calvaria (skull cap)

upper dome of the skull forming the roof of the cranial cavity.

Cranial cavity

protected space inside the skull that houses and supports the brain.

Pterion

formation of sutures at the lateral aspect of the skull joining frontal, parietal, sphenoid, and temporal bones overlying a branch of the middle meningeal artery.

Middle meningeal artery

a branch of what artery is below the pterion, meaning fracture of thin temporal bone can cause life threatening extradural haemorrhage?

Fontanelles

soft, membranous regions of the foetus/neonate where developing bones have not fully ossified allowing flexibility of skull in childbirth and as brain grows.

Anterior fontanelle

closes at 18-24 months, forming the bregma landmark.

Posterior fontanelle

closes at 3 months, forming the lambda landmark.

Frontal bone

Greater wing of sphenoid bone

Temporal bone

Styloid process

Mastoid process

Occipital bone

Parietal bone

Pterion

Lambda

Lambdoid suture

Sagittal suture

External occipital protuberance

Coronal suture

Bregma

Anterior cranial fossa

depression of the internal skull base formed from the frontal, ethmoid, and sphenoid bones, containing the frontal lobes.

Middle cranial fossa

depression of the internal skull base formed from the sphenoid and temporal bones, containing the temporal lobes.

Posterior cranial fossa

depression of the internal skull base formed from the temporal and occipital bones, containing the cerebellum.

Frontal bone

Cribiform plate of ethmoid bone

Lesser wing of sphenoid bone

Pituitary (hypophysial) fossa

Sphenoid bone

Temporal bone

Clivus

Occipital bone

Internal occipital protuberance

Telencephalon

embryological term for cerebrum, arising from the forebrain.

Diencephalon

embryological term for thalamus and accompanying structures, arising from the forebrain.

Mesencephalon

embryological term for the midbrain.

Rhombencephalon

embryological term for hindbrain, forming the pons, cerebellum, and medulla.

Cerebral cortex

outermost layer of cerebrum composed of packed nerve cells (grey matter) covering in gyri and sulci responsible for motor, sensor, and higher order functions.

Insula cortex

hidden structure of the cerebral cortex located deep to the lateral fissure, responsible for audition, pain, and homeostasis.

Nuclei

clusters of nerve cell bodies located deep inside the central nervous system.

Projection fibres (up/down)

nerve axon bundles connecting cerebral cortex with lower parts of the central nervous system.

Association fibres (forward/back)

nerve axon bundles connecting different cortical areas (gyri) in the same cerebral hemisphere.

Commissural fibres (right/left)

nerve axon bundles connecting both hemispheres, allowing interhemisphere communication.

Corpus callosum

largest commissural bundle.

Central sulcus

groove separating frontal from parietal lobe, mainly present on the lateral aspect of the cerebrum.

Lateral fissure

deep groove separating temporal from frontal and parietal lobes, mainly present on the lateral aspect of the cerebrum.

Parieto-occipital sulcus

groove separating parietal from occipital lobes, mainly present on the medial aspect of the cerebral hemispheres.

Calcarine sulcus

groove dividing occipital lobe holding the primary visual cortex, mainly present on the medial aspect of the cerebral hemispheres.

Frontal lobe

cerebral lobe responsible for executive function, behaviour, memory, and motor control.

Parietal lobe

cerebral lobe responsible for somatosensory function and sensory integration.

Occipital lobe

cerebral lobe primarily responsible for vision.

Temporal lobe

cerebral lobe responsible for audition, memory, and learning.

Limbic lobe

cerebral lobe responsible for emotion, behaviour, memory, and olfaction.

Brain stem

stalk composed of the **midbrain, pons, and medulla oblongata** containing motor and sensory white matter tracts and nuclei supplying head face with other cardiovascular and respiratory regulatory functions

Cerebellum

hind brain structure composed of central portion (vermis) and 2 hemispheres for maintenance of balance, posture, and unconscious motor movements

Peduncles

group of 3 stalks connecting motor regions of the brain and spinal cord to the cerebellum.

Frontal lobe

Central sulcus

Parietal lobe

Occipital lobe

Temporal lobe

Lateral fissure

Frontal lobe

Limbic lobe

Parietal lobe

Occipital lobe

Parieto-occipital sulcus

Calcarine sulcus

Diencephalon

Temporal lobe

Thalamus

Hypothalamus

Midbrain

Pons

Medulla oblongata

Brain stem

Cerebellum

Meninges

layers of connective tissue which cover and protect the brain and spinal cord, formed of the dura, arachnoid, and pia mater from superficial to deep.

Dura, arachnoid, pia

Recall the meningeal layers from superficial to deep.

Dura mater

tough, thick outermost membrane layer of the meninges composed of the outer periosteal layer adhered to the skull, and the inner meningeal layer.

Periosteal layer

outer layer of dura mater, adhered to the skull.

Meningeal layer

inner layer of dura mater, lining arachnoid mater.

Dural folds

meningeal layer separates from the periosteal layer, projecting downward to divide the cranium into different compartments.

Falx cerebri

large, sickle-shaped dural fold separating the hemispheres of the brain.

Tentorium cerebelli

large, crescent-shaped dural fold separating the cerebrum from the cerebellum.

Falx cerebelli

small, sickle-shaped dural fold separating the lobes of the cerebellum.

Diaphragma sellae

small, circular dural fold forming a roof over the pituitary fossa.

Dural venous sinuses

blood channels between dural layers at the dural folds.

Subarachnoid space

space between arachnoid mater and pia mater bridged by thin filaments and containing cerebrospinal fluid and blood vessels.

Thin filaments

strands of connective tissue that span across the subarachnoid space.

Arachnoid granulations

small, fluid-filled pouches of the arachnoid mater that protrude through the dura mater into the dural venous sinuses allowing CDF to enter blood.

Ventricles

four connected, fluid-filled spaces deep within the brain that produce and circulate cerebrospinal fluid.

Cerebrospinal fluid

cushioning fluid produced by the choroid plexus, also for provision of nutrients, removal of wastes, immunity, and lightening head.

Choroid plexus

specialised tissue in ventricles producing cerebrospinal fluid.

Lateral, third, cerebral aqueduct, forth

Recall the path cerebrospinal fluid flow through the ventricles.

Apertures into subarachnoid space, central canal

Describe the 2 exit points for cerebrospinal fluid from the forth ventricle.

Lateral ventricles

ventricles associated with the cerebrum.

Third ventricle

ventricle associated with the thalamus.

Cerebral aqueduct

ventricle associated with the midbrain.