The internal capsule is an anatomical structure of the cerebrum.

Anatomy

The internal capsule is bounded medially by the Nucleus caudatus and the Thalamus, and laterally by the Putamen and the globus pallidus. The Tractus corticospinalis, its most important fiber tract, runs within the internal capsule toward the Brainstem.

Schematic illustration of the internal capsule — Schematic axial section of the telencephalon including the internal capsule. Figure adapted from Gray's Anatomy.

Anterior limb of the internal capsule

The frontopontine tract and the anterior thalamic peduncle run through the anterior limb of the internal capsule. Most of the blood supply to the anterior limb is provided by capsular branches of the Arteria cerebri media[^1].

Genu of the internal capsule

The corticonuclear tract runs through the genu of the internal capsule. The blood supply to the genu is usually provided by direct vascular branches from the Arteria carotis interna[^1].

Posterior limb of the internal capsule

The posterior limb contains the corticospinal tract, corticorubral tract, as well as the superior and posterior thalamic peduncles and portions of the auditory and visual pathways. Most of the blood supply to the posterior limb is likewise provided by capsular branches of the MCA[^1] as well as by the Arteria choroidea anterior.