Cerebral Hemispheres

Ashley Davidoff MD

The Common Vein Copyright 2010

Definition

The cerebral hemispheres are the largest part of the brain and are composed of the outer layer of gray matter known as the cerebral cortex which is connected to an inner layer of white matter.  There are two cerebral hemispheres which are divided by the interhemispheric fissure and connected by the corpus callosum and other smaller commissures including the anterior commiccure and posterior commisure.  The white matter and gray matter connections also allow the cerebral hemispheres to be connected to all the other parts of the forebrain, midbrain, hindbrain, and spinal cord.

The cerebral hemispheres are divided into lobes including the frontal lobe, parietal lobe, temporal lobe and parietal lobe.

The Cerebral Hemispheres(lime green)

Part of the Forebrain (Prosencephalon)

Member of the Cerebrum (Telencephalon)  

The basic and simplest classification of the brain into forebrain midbrain and hindbrain is shown in this diagram and advanced to a more complex tree using the embryological and evolutionary terminologies. The forebrain consists of the cerebrum also called the prosencephalon, which contains the more advanced form of the brain and the thalamic structures which contain more basic structures. The cerebrum (telencephalon) itself consists of two cerebral hemispheres and paired basal ganglial structures. Each cerebral hemisphere will have gray and white matter distributed in the frontal parietal temporal and occipital lobe, with the basal ganglia being part of the gray matter deep in the cerebral hemispheres. The most important thalamic structures arising from the diencephalons include the thalamus itself and the hypothalamus. The midbrain (mesencepaholon) consists of the tectum tegmentum and cerebral peduncles. The hindbrain has two major branch points based on the evolutionary development. The pons and cerebellum(part of the metencephalon) are grouped and the medulla (part of the myelencephalon is the second branch.

Courtesy Ashley Davidoff MD Copyright 2010 All rights reserved 97686.8s