Following are features of ischemia in Anterior choroidal artery territory except –
**Core Concept**
The anterior choroidal artery (AChA) is a branch of the internal carotid artery that supplies a significant portion of the posterior limb of the internal capsule, as well as the optic tract, the lateral geniculate body, and the posterior part of the thalamus. Ischemia in the AChA territory can lead to a range of neurological deficits due to the involvement of these critical structures.
**Why the Correct Answer is Right**
The correct answer, **D. Predominant involvement of the anterior limb of internal capsule**, is incorrect because the AChA primarily supplies the posterior limb of the internal capsule, not the anterior limb. The posterior limb of the internal capsule contains the corticospinal and corticobulbar tracts, which are responsible for motor function. Ischemia in this area can lead to contralateral hemiparesis or hemiplegia (A). The AChA also supplies the optic tract, leading to contralateral homonymous hemianopia (C), a loss of vision in one half of the visual field. Hemisensory loss (B) can also occur due to involvement of the thalamus.
**Why Each Wrong Option is Incorrect**
* **Option A:** Hemiparesis is a potential consequence of AChA ischemia due to involvement of the posterior limb of the internal capsule. This option is therefore correct for the AChA territory.
* **Option B:** Hemisensory loss can occur due to ischemia in the AChA territory, as the thalamus is supplied by this artery. This option is therefore correct for the AChA territory.
* **Option C:** Homonymous hemianopia is a potential consequence of AChA ischemia due to involvement of the optic tract. This option is therefore correct for the AChA territory.
**Clinical Pearl / High-Yield Fact**
In addition to the structures mentioned above, the AChA also supplies the globus pallidus and the substantia nigra. Ischemia in this area can lead to a range of movement disorders, including parkinsonism and dystonia.
**✓ Correct Answer: D. Predominant involvement of the anterior limb of internal capsule**