## Most Common Site of Hypertensive Stroke in Internal Capsule **Key Point:** The posterior limb of the internal capsule is the most frequently affected region in hypertensive lacunar infarcts, accounting for approximately 50–60% of internal capsule strokes. ### Anatomical Basis The posterior limb contains the corticospinal tract (motor fibres) and thalamocortical radiations (sensory fibres). It is supplied by the lenticulostriate arteries (lateral perforating branches of the middle cerebral artery), which are particularly vulnerable to lipohyalinosis in chronic hypertension. ### Clinical Correlation **High-Yield:** Posterior limb infarction classically presents with **pure motor stroke** (contralateral weakness without sensory loss) or **pure sensory stroke** (contralateral sensory loss without weakness), depending on whether the infarct involves motor or sensory fibres. ### Comparative Frequency of Internal Capsule Stroke Sites | Site | Frequency | Typical Presentation | Arterial Supply | |------|-----------|----------------------|-----------------| | Posterior limb | 50–60% | Pure motor or pure sensory | Lenticulostriate (MCA) | | Genu | 20–30% | Facial weakness, dysarthria | Lenticulostriate (MCA) | | Anterior limb | 10–15% | Cognitive/behavioural changes | Lenticulostriate (MCA) | | Retrolenticular part | <5% | Visual field defects | Posterior choroidal (PCA) | **Clinical Pearl:** The posterior limb is the "watershed" of hypertensive microvascular disease because the lenticulostriate arteries are end-arteries with poor collateral supply, making them exquisitely sensitive to chronic hypertension-induced lipohyalinosis. **Mnemonic:** **PALS** — **P**osterior limb = **A**rtery (lenticulostriate) = **L**acunar = **S**troke (most common).
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.