Download Cerebral hemispheres

‫بسم هللا الرحمن الرحیم‬
Cerebrum
Cerebral hemisphere
Cortex
White mater
Function
Related structure
Figure 12.2b
- The cerebrum is the largest part of the brain.
- Situated in the anterior and middle cranial fossae of the skull
and occupying the whole concavity of the vault of the skull.
- lt may be divided into two parts:
1. the diencephalon, which forms the central core,and
2. the telencephalon, which forms the cerebral hemispheres.
- The diencephalon consists of the third ventricle and the structures
that form its boundaries.
- It extends posteriorly to the point where the third ventricle
becomes continuous with the cerebral aqueduct and anteriorly
as far as the interventricular foramina.
- Thus,the diencephalon is a midline structure with symmetrical
right and left halves.
• The diencephalon can be divided into four
major parts:
•
•
•
•
(1) the thalamus
(2) the subthalamus
(3) the epithalamus,
(4) the hypothalamus.
A bundle of nerve fibers, which are afferent fibers to the habenular nucleus, forms a ridge along the superior
margin of the medial surface of the diencephalon and is called the stria medullaris thalami
Each Cerebral hemisphere is made
from:
 Cortex, a superficial gray mater
 Centrum Semiovale, a deep massive
neuronal processes, (white mater)
 Deep basal nuclei
 Lateral ventricle
General Arrangement of the Cerebrum:
Cerebral hemispheres:
 derived from the embryological Telencephalon’
 underlying white matter (afferent & efferent
fibres)
 deep nuclear masses = basal ganglia
The two cerebral hemispheres are:
 Separated by the great longitudinal fissure
 Joined by the corpus callosum (nerve fibre system,
General Arrangement of the Cerebrum:
 divided into 4 lobes:




Frontal
Parietal
Temporal
Occipital
 additional structure:
 Insula (buried deep below the lateral fissure)
Development of Sulci
Sulci appear at predictable points in fetal development with the most
prominent sulci (e.g., Sylvian fissure) appearing first.
Cerebral hemispheres
• Each of them has:
• 3 poles :
– Frontal, Occipital, Temporal
• 3 Borders :
– Superior, inferomedial & inferolateral
• 3 Surfaces :
– Superolateral, medial & inferior
– Inferior surface : orbital & tentorial
Each surface included some suci & gyri
• Sulcus ----------- A depression or groove in the
surface of the cerebrum that helps increase surface
area of the cerebrum.
• Gyrus ------------ An elevated ridge that projects
upwards between the sulci of the cerebrum and also
helps increase surface area of the cerebrum.
Defining the lobes
frontal lobe
central (rolandic)
sulcus
parietal lobe
occipital
lobe
temporal lobe
sylvyan (lateral) sulcus
Sulci of lateral view
• Lateral sucus:
– Anterior horizontal
– Anterior ascending
– Posterior branch
• Central sulcus :
– Superior frontal &
– Inferior frontal sulci
• Superior & middle temproal gyri
Sulci of medial view
• Cingulate sulcus
• Parieto – occipital sulcus
• Calcarine sulcus
LOBE
1.
2.
3.
4.
5.
Frontal Lobe
Parietal Lobe
Occipital Lobe
Temporal Lobe
Cinguli Lobe
• Precntral Sulcus
Sulci of inferior view
• Tentorial portion:
– Collateral sulcus
– Fronto - occipital sulcus
• Orbital portion
– Oribital sulci