Internal Capsule and Transcapsular Gray Striae
6611
Surgical Correlation
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Internal capsule and transcapsular gray striae. In this lateral dissection of the right cerebrum, the lentiform nucleus has been removed to reveal the internal capsule, a large, vertically oriented, deeply situtated mass of white matter. The internal capsule contains ascending and descending projection fibers that interconnect the cerebral cortices above, with a number of subcortical structures including the thalamus, brainstem and spinal cord, below. Dorsally, the internal capsule is continuous with the massive fan-shaped corona radiata. Traversing the anterior limb of the internal capsule are narrow strands of gray matter known as transcapsular, or caudatolenticular, gray striae. The latter are bridges of gray matter that interconnect the caudate nucleus (located medial to the internal capsule) and the rostral part of the putamen (located lateral to the internal capsule). Lateral to the corona radiata course fibers of the superior longitudinal fasciculus. The latter fasciculus is a long associational fiber tract that interconnects the frontal lobe with the parietal, occipital and temporal lobes. In the lower part of the image is seen the optic radiation, including its anterior extension into the temporal lobe known as Meyer's loop (arrow). (Image courtesy of PA Rubino)