anatomy of the brain for radiologist

8/12/2019 Anatomy of the Brain for Radiologist

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Cranial Anatomy

Dr. Anggraini Dwi S.,SpRad(K)

Topographic Anatomy

Cerebral Hemisphere

There are four lobes of cerebral hemisphere, the frontal, parietal, occipital, and

temporal lobes. The frontal lobe is separated from the parietal lobe is separated from parietal

lobe by the central (Rolandic) sulcus, the parietal lobe is separated from occipital lobe by

parieto-occipital sulcus, and the temporal lobe is separated from the frontal and parietal lobes

by the sylvian (lateral) fissure.

The frontal lobe consist of:

- Precentral gyrus (the primary motor strip of the cerebral cortex)- The 3 frontal gyri anterior to the motor strip : the superior, middle, and the inferior frontal

gyri

-Medial surface : cingulate gyrus, gyrus rectus extending along medial basal surface of theanteror cranial fossa.

The parietal lobe contains :

- The post central gyrus (the center for somatic sensation)- The supramarginal gyrus just above the temporal lobe- The angular gyrus near just apex of the temporal lobe- 2 superficial gyri, superior and inferior parietal lobules, separated by interparietal

sulcus

- On its medial side the precuneus gyrus is present

The temporal lobe

contains the brain-functioning elements of speech, memory, and hearing. On the

superior aspect of the brain temporal lobe can be seen :

- Sperior- Middle- Inferior temporal gyri


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Deep to the sylvian fissure is the insula, or isle of Reil, which is bounded laterally by

the opercular regions. Other structures that located near temporal lobe are operculum, limen

and insula, parahippocampus gyrus, hippocampus, amygdala.

The occipital lobe is the lobe most commonly associated with visual function. At its

apex is calcarine sulcus, with the cuneate gyrus just above it, and calcarine just below it.

Diencephalon contains the thalamus and hypothalamus. The thalamus has

many nuclei, the most important of which are the medial and lateral geniculate nuclei

associated with auditory and visual functions. The thalamus located on the other side of third

ventricle and connects across the midline by massa intermedia. The hypothalamus is located

at the floor of the third ventricle, above optic chiasm and suprasellar cistern. The

hypothalamus is connected to the posterior pituitary via infundibulum or stalk.

Brain Stem

The mesencephalon

differentiates into the midbrain. The midbrain is the site of the third and fourth cranial

nerves, contain red nucleus, substantia nigra, and cerebral aquaduct or aquaduct of Sylvius.

White matter tracts pass through the the midbrain, and the midbrain separated into the

tegmentum and tectum. The tectum or roof, consist of the quadrigeminal plate (corpora

quadrigemina) which houses superior and inferior colliculi. The tegmentum contains of fiber

tracts, red nuclei, third and fourth cranial nerve nuclei, and periaquaductal grey matter. The

substantia nigra is anterior border of the tegmentum. Anterior to the tegmentum are the

cerebral peduncles.

The metencephalondevelops into the pons and cerebellum. The pons contains the

nuclei for cranial nerves V,VI,VII and VIII. Pontine white matter tracts transmit sensory and

motor fibers to the face and body. The pons also houses maor connections of the reticular

activating system for vital functions.

The myencephalonbecomes the medulla. The medulla contains the nuclei for cranial

nerves IX,X,XI,XII. The sensory and motor tracts to and from the face and brain are

transmitted through the medulla.


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Cerebellum

The cerebellum is located in the space posteriro to the brain stem. The anatomy of the

cerebellum is complex, with many named areas. For simplicity, people separate into the

superior and inferior vermis and reserve the term cerebellar hemisphere for the rest of lateral

and central portions of cerebellum.

Corpus Callosum

The medial surface of the brain in the midline is dominated by the corpus callosum.

This is the latge white matter tract that spans the two hemispheres. Its named parts include

the rostrum, the genu, the body or trunk and the splenium.

Othe white matter tracts that cross the midline include the anterior commissure, and

the posterior commissure.

Deep grey nuclei

The basal ganglia are known by a number of names. These grey matter structures lie

between insula and midline. The globbus pallidus is the medial grey matter structure

identified just lateral to the genu of the internal capsule. Superficial to it lies the putamen.

The caudate nucleus head indents the frontal horns of the lateral ventricles, and is anterior to

the globus pallidus, however the body of the caudate couses over the globus pallidus,

paralelling the lateral ventricle and ending in a tail of tissue near the amygdala.

Other term : corpus striatum (all three structures + amygdala), lentiform or lenticular

nuclei (the globus pallidus+putamen).

The largest deep grey matter structure in the infratentorial space is dentate nucleus,

has connections to the red nuclei and to the thalami. The most importan functions of this

structure is in coordinative movements of the limbs and trunk.


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Ventricular system

The normal volume of cerebrospinal fluid (CSF) in the entire CNS is approximately

150mL, 75 mL distributed arround the spinal cord, 25 mL within the ventricular system, and

50 mL surrounding the cortical sulci and in the cisterns at the base of the brain. The normal

production of CSF has been estimated to be approximately 450 mL/day. The CSF was

resorbed by the arrachnoid villi from the extracellualar fluid.

Cranial nerves

The cranial nerves can be organized in groups of four. Cranial nerves I through IV

arise from the midbrain (occulomotor and trochlear) or above (olfactory and optic nerve).

Cranial nerve V through VIII arise from the pons. The last four cranial nerves arise from the

medulla.

Vascular Anatomy

Intracranial circulation is supplied by paired internal carotid arteries and paired

vertebral arteries. It consists of anterior cerebral artery system, middle cerebral artery system,

vertebral arteries and basilar artery branches.

Venous Anatomy

It is importan to evaluaste the superficial drainage, deep supratentorial drainage and

deep infratentorial drainage.


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References :

1. Galluci M, Capoccia S., Catalucci A. Radiographic Atlas of The Skull and BrainAnatomy. Berlin, 2005. Springer-Verlag

2. Grossman RI., Yousem DM. Neuroradiology. Elsevier, Philadelphia, 2003: 37-963. Fitzgerald MJT., Gruener G., Mtui E. Clinical Neuroanatomy and Neuroscience.

2012. Saunders-Elsevier.

4. Tamraz JC., Comair YG. Atlas of Regional Anatomy of the Brain Using MRI. NewYork 2006.Springer-Verlag.

anatomy of the brain for radiologist

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