Underneath the cerebrum at the center of the brain

1. Marwan Alhalabi MD PhD
Professor in Reproductive Medicine
Faculty of Medicine
Damascus University
&
Clinical Medical Director
Orient Hospital
Assisted Reproduction Center
Damascus, Syria.

2. In the 18th century, the
corpus callosum was
considered the site of the
soul (Maurice Ptito), and in
the early 20th it was
assigned the mere role of
preventing the cerebral
hemispheres from
collapsing onto each other

3. It was only in the 1950's that
the corpus callosum, in the
pioneering work of Myers
and Sperry, was attributed
the function of transferal of
information between the
two hemispheres

4. This was followed by the
development, in the early
1960's, of a surgical
intervention aimed at
reducing the
interhemispheric
transmission of abnormal
electrical discharges in
epileptic patients

5. Underneath the cerebrum at the center of the brain.

7. Ø Largest connective pathway
Ø 200 million nerve fibers
Ø Connects left & right
hemisphere
Ø “Communication”

9. l Transfers the following:
l Motor information
l Sensory information
l Cognitive information
l “ALL THROUGH LEFT & RIGHT HEMISPERES!”

10. 1. Splenium
2. Body
3. Genu
4. Rostrum
5. Isthmus

12. Motor
Somatosensory Auditory
Visual
200,000,000 Neurons connect each
hemisphere

13. • Developmental absence of the
corpus callosum: Agenesis (ACC)
• Partial ACC
• Complete ACC
• Each of these may be:
• Isolated: ACC with no other abnormalities
• Complex: ACC with other abnormalities

15. • Incidence – difficult to estimate (asymptomatic
individuals)
• There are no large studies
• 1.4 per 10.000 live births (California Birth Defect
Monitoring Program)
• Prevalence of associated brain abnormalities - 45,8%
(posterior fossa, interhemispheric cysts and neuronal migration disorders)
• The overall rate of chromosomal abnormality - 17,8%
(consider - chromosomal analysis, CGH)

16. • Measurement of CC size – recommended by some authors
Achiron R,Achiron A..Ultrasound Obstet Gynecol 2001; 18: 343–347.

19. Corpus callosum
• By 18-20 weeks’ gestation – final shape

20. Corpus callosum:
• Approach: mid-sagittal or mid-coronal plane of the brain
• Multiplanar sonography or TVS – useful
• Mid-sagittal view – thin anechoic space
• Mid-sagittal view – pericallosal artery as a marker (especially in
resolution-related difficulties )
• 3D/4D reconstruction

26. Absence of the cavum septi pellucidi (CSP)
• Not specific to ACC (holoprosencephaly,
hydrocephalus, septo-optic dysplasia,
schizencephaly, encephalocele, porencephaly and
hydranencephaly).
• In partial ACC - CSP is usually present

28. Fused frontal horns mimic the presence of CSP

30. Abnormalities of the ventricles
• Colpocephaly - dilatation of the atria
and occipital horns of the lateral
ventricles
• Result of the absence of CC posterior portion, which allows
expansion of the occipital horns.
• Usually not associated with progressive ventriculomegaly

31. • Lateral displacement of
Lateral Ventricle on
coronal views.
• Upward displacement
of the third ventricle,
which reaches the level
of the lateral ventricles

35. Abnormal course of the pericallosal artery
• Complete ACC: the semicircular loop of the pericallosal artery is lost
• Partial ACC: the pericallosal artery follows the anterior part of the CC
but then loses its normal course where the CC disappears posteriorly;

38. Widening of the
interhemispheric fissure
• Increased separation of the
hemispheres
• 3 parallel echogenic lines (the
middle - falx cerebri)
• The lateral ones representing the
medial borders of the separated
hemispheres

41. Signs and symptoms
• Vary greatly among individuals
• Some characteristics common in individuals with callosal disorders include
1. Poor motor coordination,
2. Delays in motor milestones such as sitting
and walking,
3. Delayed toilet training,
4. Chewing and swallowing difficulties
5. Vision impairments,
6. Hypotonia
7. Low perception of pain, .
8. sometimes seizures, spasticity, early
feeding difficulties

42. • Associated syndromes
• ACC can occur as an isolated condition or in combination with other
cerebral abnormalities, including
• Arnold-chiari malformation,
• Dandy-walker syndrome,
• Andermann syndrome(motor and sensory neuropathy)
• Schizencephaly (clefts or deep divisions in brain tissue)
• Holoprosencephaly (failure of the forebrain to divide into
lobes.)
• Aicardi Syndrome.
• Cephalocele.

43. Cause
• Agenesis of the corpus callosum is caused by
disruption to development of the fetal brain
between the 3rd and 12th weeks of pregnancy.
• In most cases, it is not possible to know what
caused an individual to have ACC or another
callosal disorder.

44. Cause
• However, research suggests that some possible causes may include
• chromosome errors,
• inherited genetic factors,
• prenatal infections or injuries,
• prenatal toxic exposures,
• structural blockage by cysts or other brain abnormalities
• metabolic disorders.

45. Treatment
• There are currently no specific medical treatments for
callosal disorders, it usually involves management of
symptomsand seizures if they occur.
• Patients may benefit from a range of
• developmental therapies,
• educational support, and services.

46. • Depends on coexistence of other
abnormalities
• Association with cortical disorders – poor
prognosis
• Normal or borderline intellectual
development – in case of isolated
• Pediatric data suggest – more than 90%
mental retardation or severe
abnormalities

48. Only& The& Rostrum& (1),& Genu& (2)& And& Body& (3)& Are& Visible;& The& Splenium& Is&
Missing.&The&Corpus&Callosum&Is&Short&Posteriorly&And&Does&Not&Seem&To&Overlay&
The&Quadrigeminal&Plate

53. • Agenesis of corpus
callosum (ACC)
• Cortical heterotopia,
• Infantile spasm,
• Chorioretinopathy,
• Mental retardation with
or without associated
vertebral anomalies.
• X Linked Recessive