Corpus: Internal capsule

The internal capsule is part of the cerebrum (telencephalon). It is bounded internally by the caudate nucleus and the thalamus and externally by the putamen and the pallidum. The internal capsule consists of white matter and contains some important fibre connections from the cerebral cortex to the pons, medulla oblongata and medulla spinalis.

Macroscopically, the capsula interna is subdivided into

• Crus anterius capsulae internae - between the caudate nucleus and putamen
• Crus posterius capsulae internae - between the thalamus and putamen

Between the two legs lies the genu capsulae internae ("capsular knee"), directly medial to which is the interventricular foramen.

Crus anterius[Bearbeiten]

• Descending tracts: Fibrae frontopontinae
• Ascending tracts: "anterior thalamic stalk" (fibres from the thalamus to the frontal lobe)

Genu capsulae internae[Bearbeiten]

• Ascending tracts: "middle thalamic stalk" Tractus corticonuclearis

Crus posterius[Bearbeiten]

• Descending tracts: Tractus corticospinalis (later: pyramidal tract), tractus corticonuclearis and tractus temporopontinus
• Ascending tracts: "upper thalamic peduncle" (fibres from the thalamus to the somatosensory cortex), "posterior thalamic peduncle" (fibres from the thalamus to the temporal and occipital lobes), auditory and visual radiation

The crus anterius of the capsula interna is supplied by the arteriae centrales anteromediales from the arteria cerebri anterior and the arteria centralis longa. The genu receives its arterial supply from the central anterolateral arteries, which originate from the middle cerebral artery. The posterior crus belongs to the supply area of the anterior choroidal artery (from the internal carotid artery).

50-60% of hypertensive mass haemorrhages are localised in the area of the internal capsule. The anterolateral central arteries are a predilection site for intracerebral haemorrhages. Frequent complications are a ventricular hernia and the resulting hydrocephalus.