â– STRUCTURAL ANATOMY: The internal capsule is a compact band of projection fibers (both ascending sensory and descending motor) that intermediates the cerebral cortex and lower brainstem. It consists of an Anterior Limb, Genu, Posterior Limb, and Retrolenticular/Sublenticular parts.
â– SEGMENTAL BLOOD SUPPLY DETAILS:
1. Anterior Limb: Supplied primarily by the anteromedial central branches of the Anterior Cerebral Artery (ACA) and Heubner's recurrent artery.
2. Genu: Supplied by direct branches from the Internal Carotid Artery (ICA) and some lateral striate branches of the Middle Cerebral Artery (MCA).
3. Posterior Limb: Houses the crucial descending Corticospinal (motor) tract fibers and ascending thalamocortical sensory pathways. It is supplied by the Lenticulostriate arteries (branches of the M1 segment of the MCA) and the Anterior Choroidal Artery (a branch of the ICA).
â– EXAM CLINICAL NOTES: The Lenticulostriate arteries are thin, tortuous vessels that lack anastomoses and branch at right angles. This makes them highly susceptible to hypertension-induced Charcot-Bouchard aneurysms.
â– MICROSCOPIC PATHOBIOLOGY:
Histopathologic biopsy reveals cellular atypia, pleomorphism, lipid vacuolar engorgement, or characteristic structural inclusions (e.g., specific nuclear changes, cytoplasmic inclusions) which are diagnostic for the pathology.
â– SECONDARY PREVENTION METRICS:
Implementing long-term dietary adaptations, physical therapy, and compliance aids reduces the rate of recurring acute crises by more than half.
[HY-BOARD-1226]
🌟 Dynamic Clinical Key:
Rupture of the Lenticulostriate arteries (the 'arteries of cerebral hemorrhage') or embolic occlusion of the posterior limb results in a classic pure motor stroke, presenting as contralateral hemiplegia of the face, arm, and leg with no sensory or cortical deficits. Confirm histologic findings with immunophenotypic cell markers using flow cytometry. Patient education regarding warning signs and therapy adherence is the cornerstone of secondary prevention.