Lab 10 (ƒ2) - Internal Organization of the Brain
Overview of the External Capsule and Claustrum
A thin, slightly sinuous strip of gray matter, the Claustrum, 
lies between the lateral boundary of the putamen and the Insula, the strip of cortex which lies deep within the lateral fissure. The claustrum is of obscure significance.
The thin strip of white matter between the putamen and claustrum is called the External Capsule, and the white matter separating the claustrum from the insular cortex is the Extreme Capsule. The external and extreme capsules contain association fibers, as compared to the projection fibers within the internal capsule.