On axial CT of the brain at the level of the third ventricle, the internal capsule is seen as a V shaped white matter band. Which structure divides the anterior limb from the posterior limb of the internal capsule?
- A Thalamostriate vein
- B Genu of the internal capsule ✓
- C Anterior commissure
- D Column of the fornix
Correct answer: B. Genu of the internal capsule
Explanation
The internal capsule bends around the medial aspect of the globus pallidus, and the bend, called the genu, separates the anterior limb from the posterior limb. The anterior limb lies between the caudate head and the lentiform nucleus carrying frontopontine fibres, while the posterior limb lies between the thalamus and lentiform nucleus and carries the corticospinal tract. This anatomy underlies the classic lacunar syndromes of pure motor stroke.
Reference: Gray's Anatomy, 42nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.