Interthalamic adhesion
Encyclopedia
The medial surface of the thalamus
constitutes the upper part of the lateral wall of the third ventricle
, and is connected to the corresponding surface of the opposite thalamus by a flattened gray band, the Interthalamic adhesion (massa intermedia, middle commissure, gray commissure).
In non-human mammals it is a large structure. In humans this mass averages about 1 cm in length in its antero-posterior diameter. It sometimes consists of two parts and occasionally is absent. The interthalamic adhesion is found in 70-80% of humans. It is present more often in females and larger than in males by an average of 53 percent. http://www3.interscience.wiley.com/cgi-bin/abstract/109691976/ABSTRACT?CRETRY=1&SRETRY=0 When absent in development, no noticeable deficit has been observed.
It contains nerve cells and nerve fibers; a few of the latter may cross the middle line, but most of them pass toward the middle line and then curve laterally on the same side. It is still uncertain whether the interthalamic adhesion contains fibers that cross the mid-line and for this reason it is inappropriate to call it a commissure
. In 1889, a Portuguese anatomist by the name of Macedo examined 215 brains, showing that male humans are approximately twice as likely to lack an interthalamic adhesion as are female humans. He anecdotally attributed the finding to a "prevailing feature of people deprived of [the interthalamic adhesion] is to present in their psychical acts a remarkable precipitation, joined to a certain dysharmony between internal and external feelings." It is noted to be enlarged in patients with Chiari II malformations.
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
constitutes the upper part of the lateral wall of the third ventricle
Third ventricle
The third ventricle is one of four connected fluid-filled cavities comprising the ventricular system within the human brain. It is a median cleft between the two thalami, and is filled with cerebrospinal fluid ....
, and is connected to the corresponding surface of the opposite thalamus by a flattened gray band, the Interthalamic adhesion (massa intermedia, middle commissure, gray commissure).
In non-human mammals it is a large structure. In humans this mass averages about 1 cm in length in its antero-posterior diameter. It sometimes consists of two parts and occasionally is absent. The interthalamic adhesion is found in 70-80% of humans. It is present more often in females and larger than in males by an average of 53 percent. http://www3.interscience.wiley.com/cgi-bin/abstract/109691976/ABSTRACT?CRETRY=1&SRETRY=0 When absent in development, no noticeable deficit has been observed.
It contains nerve cells and nerve fibers; a few of the latter may cross the middle line, but most of them pass toward the middle line and then curve laterally on the same side. It is still uncertain whether the interthalamic adhesion contains fibers that cross the mid-line and for this reason it is inappropriate to call it a commissure
Commissure
A commissure is the place where two things are joined. The term is used especially in the fields of anatomy and biology.In anatomy, commissure refers to a bundle of nerve fibers that cross the midline at their level of origin or entry .* The most common usage of the term refers to the brain's...
. In 1889, a Portuguese anatomist by the name of Macedo examined 215 brains, showing that male humans are approximately twice as likely to lack an interthalamic adhesion as are female humans. He anecdotally attributed the finding to a "prevailing feature of people deprived of [the interthalamic adhesion] is to present in their psychical acts a remarkable precipitation, joined to a certain dysharmony between internal and external feelings." It is noted to be enlarged in patients with Chiari II malformations.
External links
- Image at Harvard UniversityHarvard UniversityHarvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
- Diagram at csuchico.edu (labeled as Massa intermedia)
