The corpus callosum is the largest commissure in the brain, connecting the left and right cerebral hemispheres and facilitating communication for motor, sensory, and cognitive processes. It comprises four parts: genu, rostrum, trunk, and splenium, and is well-supplied with blood, minimizing infarct risks. Clinical conditions related to the corpus callosum include agenesis, impingement syndrome, and disconnection syndrome, affecting visual perception, motor skills, and interhemispheric communication.

1. - CHAITRA CHINMAYEE M K
CORPUS CALLOSUM

2. • The corpus callosum is the
largest commissure of the
brain.
• It is a thick band of nerve
fibres that connects the left
and right sides of the
cerebral cortex, allowing
communication between them.
• It transfers motor, sensory,
and cognitive information
between the cerebral
hemispheres.
CORPUS CALLOSUM

3. EXTERNAL FEATURES
• Corpus callosum forms a massive
arched interhemispheric bridge
in the floor of the median
longitudinal cerebral fissure
connecting the medial surfaces
of the two cerebral
hemispheres.
• In sagittal section, it is seen as
a C-shaped mass of white
fibres on the medial surface of
the hemisphere forming the
roof of the lateral ventricle.
• The concave inferior aspect of
corpus callosum is attached with
the convex superior aspect of
the fornix by septum
pellucidum.

4. PARTS OF CORPUS CALLOSUM
The Corpus Callosum has four parts:-
• Genu - It is thick curved anterior
extremity of corpus callosum which
lies 4 cm behind the frontal pole.
• Rostrum: The genu extends
downwards and backwards as a
thin prolongation to join the lamina
terminalis forming the rostrum.
• Trunk/Body: The trunk is the main
part of the corpus callosum
between its anterior and posterior
extremities.
• Splenium: The splenium is the
massive posterior extremity of the
corpus callosum, lying 6 cm in front
of the occipital pole whose fibres
connect the parietal, temporal, and
occipital lobes of the two
hemispheres.

5. FUNCTIONS OF CORPUS CALLOSUM
The corpus callosum is the largest fiber bundle in the brain, largely
responsible for interhemispheric transfer of information which is
essential for bilateral responses and learning processes.

6. BLOOD SUPPLY
The blood supply to the corpus callosum is rich and strengthened by
anastomoses hence, the area is rarely affected by infarcts.
Arterial Supply:-
• Callosal branches of the pericallosal artery
• Posterior pericallosal artery, is a branch of the posterior cerebellar artery
• Occasionally, anterior communicating artery via either the median callosal or
the subcallosal artery

7. Venous Drainage:-
Callosal veins and Callosocingulate veins  subependymal
veins  septal veins medial atrial vein  internal
cerebral veins

8. CLINICAL ASPECTS
Agenesis of the corpus
callosum
This is a rare congenital disorder, and
is defined as the partial or complete
absence of the corpus callosum.
The disease usually occurs between
the 3rd and 12th week of
gestational life, the period when
neurological development is at its peak.
Symptoms –
Hypotonia, swallowing and chewing
difficulties, low pain perception, delays
in motor milestones such as walking
and sitting, poor motor coordination.
Seizures occur in up to two thirds of
patients and symptoms also depend on
the presence of associated brain
malformations.

9. Stereopsis /binocular vision
This is our ability to perceive depth, and is dependent
on our corpus callosum, allowing us to interpret visual
information from one eye in conjunction with the visual
information from our other eye.

10. Corpus callosum impingement syndrome
Impingement of the corpus callosum fibres on the inferior
free margin of the falx cerebri. It usually results from
longstanding hydrocephalus. Ischaemia results and
eventually causes atrophy. It does not usually produce
symptoms.
Disconnection syndrome
This is a syndrome that occurs when the connection
between the two hemispheres is disrupted, either as a
result of brain surgery, stroke or trauma. The patient
may be completely normal to their family and friends, but
specific tests elicit the abnormalities.

11. CLINICAL SIGNIFICANCE
Corpus Callosotomy
The corpus callosum is cut through in an effort to limit the spread of
epileptic activity between the two halves of the brain.
It is a pallative surgical procedure for the treatment of medically
refractory epilepsy.
After the operation the brain has much more difficulty sending messages
between the hemispheres. Although the corpus callosum is the largest
white matter tract connecting the hemispheres, some limited
interhemispheric communication is still possible via the anterior
commissure and posterior commissure.

12. VARIATION IN SEXES
Advanced analytical techniques of computational
Neuro-anatomy, showed that sex differences
were clear but confined to certain parts of the
corpus callosum, and that they correlated with
cognitive performance in certain tests.
Recent study using MRI found that the mid-
sagittal corpus callosum cross-sectional area is, on
average, proportionately larger in females.
Using diffusion tensor techniques on MRI machines
anisotropy can be measured and used as an indirect
measurement of anatomical connection strength.
These sequences have found consistent sex
differences in human corpus callosal shape and
microstructure.
Front portion of the human corpus callosum was found
to be 11% larger in left handed and ambidextrous
people than right-handed people. This difference was
evident in the anterior and posterior regions of the
corpus callosum, but not in the splenium.

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