Anatomy of the Brain

Falx cerebri

A midsagittal fold in the dura mater forms falx cerebri and separate the right and left hemispheres of the cerebrum.

CN VI

Abducense nerve (motor)

CN XI

Accessory nerve (motor)

Anterior commissure

Another tract of withe matter connecting the cerebral hemisphere.

Infundibulum

Anterior to the mamillary bodies is the infundibulum, the stalk that attaches the pituitary gland to the hypothalamus.

Septum pellucidum

At the midline of brain, the lateral ventricles are separated by a thin membrane called septum pellucidum.

Mesencephalon

Inferior to the diencephalon is the mesencephalon (midbrain) of the brain stem.

choroid plexus

Inside of each ventricles is specialized capillaries, where the CSF is produced.

Insula

Cutting into lateral sulcus and peeling away the temporal lobe reveals a fifth lobe, the insula.

Ventricles

Deep in the brain are four chambers called ventricles.

Arachnoid mater

Deep to the dura mater is the arachnoid mater, named after weblike connection this membrane has with the underlying pia mater. The arachnoid mater forms a smooth covering over the brain.

Cranial Meninges layers

Dura mater, Arachnoid mater, Pia mater (from outer layer to inner layer)

Sulcus

Each shallow grooves of cerebral cortex is called sulcus.

Gyrus

Each small folds of cerebral cortex is called gyrus.

CN VII

Facial nerve (mixed)

CN X

Vagus nerve (mixed)

CN VIII

Vestibulocochlear nerve (sensory)

Diencephalon

Inferior to the cerebrum are the thalamus and hypothalamus, which together make up the diencephalon.

Subdural space

Between dura mater and the underlying arachnoid mater is subdural space.

subarachnoid space

Between the arachnoid mater and pia mater is subarachnoid space, where the CSF circulate.

Arachnoid granulation

CSF circulate around brain and spinal cord and is reabsorbed at arachnoid granulations, which project into veins of dural sinuses.

CSF circulating pathway

CSF circulates from the lateral ventricles through the interventricular foramen and enters the third ventricle, a small chamber in the diencephalon. CSF in third ventricle passes through the cerebral aqueduct and enters the fourth ventricle between the brain stem and the cerebellum.

Cerebrospinal fluid (CSF)

Circulating between cranial meninges layer and Cushions the brain and prevent the brain from contacting the cranial bones during head injuries.

CN IX

Glossopharyngeal nerve (mixed)

CN XII

Hypoglossal nerve (motor)

Precentral gyrus

Immidietly anterior to the central sulcus is precentral gyrus, which contains the primary motor cortex , where the voluntary commands to skeletal muscles are generated.

Arbor vitae

In sagittal section, the withe matter of cerebellum is apparent. Because this tissue is highly branched, is called arbor vitae.

Cerebellar nuclei

In the middle of arbor vitae are the cerebellar nuclei, which function in the regulation of involuntary skeletal muscle contraction.

CN III

Oculomotor nerve (motor)

CN I

Olfactory nerve (sensory)

Mamillary bodies

On the inferior surface of the brain, a pair of mamillary bodies are visible inferior to the hypothalamus. These bodies are hypothalamic nuclei that control eating reflexes for licking, chewing, sucking, and swallowing.

Pia mater

On the surface of the brain is the pia mater, which contains many blood vessels supplying the brain.

Lateral ventricles

One in each cerebral hemisphere, extend deep into the cerebrum as horseshoe-shaped chambers.

CN II

Optic nerve (sensory)

Frontal lobe

The anterior cerebrum is the frontal lobe, and the prominent central sulcus, located approximately midposterior, separate frontal lobe from parietal lobe.

Corpora quadrigemina

Posterior to the cerebral aqueduct is the corpora quadrigemina, a series of four bulges next to the pineal gland of the diencephalon.

Tentorium cerebelli

Posteriorly, the dura mater folds again as the tentorium cerebelli, and separates the cerebellum from cerebrum.

Cerebral peduncles

The anterior mesencephalon between pons and hypothalamus, a group of withe fibers that connecting the cerebral cortex to the other parts of the brain.

Pyramids

The anterior surface of the medulla oblongata has two prominent fold called pyramids where some motor tracts cross over, or decussate, to the opposite side of the body.

Cranial Meninges

The brain is encased in layers of tough, protective cranial meninges.

Cerebral Cortex

The cerebral hemisphere are covered with cerebral cortex of gray matter, when neurons are not myelinated.

Corpus callosum

The cerebral hemisphere is connected by a deep, thick tract of white matter called corpus callosum, which bridges to the cerebral hemisphere at the base of longitudinal fissure.

Longitudinal fissure

The cerebrum is divided into right and left cerebral hemisphere by deep groove known as longitudinal fissure.

Pineal gland

The con-shaped structure superior to the mesencephalon positioned between the cerebrum and cerebellum.

Hypothalamus

The hypothalamus is the floor of the diencephalon.

Fornix

The inferior portion of the corpus callosum is the fornix, withe tract connecting structure of limbic system (emotional brain).

Pons

The large, swollen region of brain stem just inferior to the mesencephalon. The pons function as a relay station to direct sensory information to the thalamus and cerebellum. It also contains certain sensory , somatic motor, and autonomic cranial nerve nuclei.

Cerebrum

The largest and the complex region of brain is called cerebrum. Conscious, thought, intellectual reasoning, and memory processing and storage all take place in the cerebrum.

Lateral sulcus

The lateral sulcus defines the boundary between the large frontal lobe and the temporal lobe of the lower lateral cerebrum.

Brain Stem

The medulla oblongata, pons, mesencephalon (midbrain) are collectively called the brainstem.

Medulla oblongata

The most inferior part of the brain stem, connecting brain to spinal cord. The sensory information in ascending tracts in spinal cord enter the brain at medulla oblongata, and motor command descending tracts passes the medulla oblongata and enter the spinal cord. Medulla oblongata function as an autonomic center for visceral functions.

Occipital lobe

The occipital lobe lies under occipital bone of posterior skull.

Optic chiasm

The optic nerve is easy to identify as the x-shaped structure at the optic chiasm inferior to the hypothalamus.

Cerebellum

The oval mass posterior to the brain stem is called cerebellum.

Interthalamic adhesion

The oval structure in diencephalon that connects the right and left sides of the thalamus.

Postcentral gyrus

The postcentral gyrus, on the parietal lobe, contains the primary sensory cortex, where the general senses of touch is perceived.

Thalamus

The thalamus region of diencephalon maintains a crude sense of awareness. All sensory impulses except olfactory and proprioception (the sense of muscle, bone, and joint position) and are relayed to the proper sensory cortex for interpretation. Nonessential sensory data are filter out by thalamus and do not reach to the sensory cortex.

Dura mater

The tough, outer layer meningeal covering, consist of an endosteal layer fused with the periosteum of the cranial bones and a meningeal layer that faces the arachnoid mater. Endosteal layer: outer dural layer Meningeal layer: inner dural layer

Inferior colliculi

The two members of inferior pair of bulges are the inferior colliculi, which function as auditory reflex center to move the head, to locate and follow the sounds.

Superior colliculi

The two members of superior pair of bulges are the superior colliculi, which function as visual reflex center to move the eye and head, and keep an object center on the retina of the eye.

CN V

Trigeminal nerve (mixed)

CN IV

Trochlear nerve (motor)

Falx cerebelli

the dural fold between the hemispheres of the cerebellum.