Penetrating vessels and lacunar strokes

Vascular anatomy

So-called penetrating vessels responsible for lacunar infarcts are all small vessels that branch directly off a large parent artery as described below. This transition from large to small vessels apparently makes them particularly vulnerable to the effects of hypertension and resultant arteriolosclerosis.

  • Internal carotid artery
    • anterior choroidal artery >> LGN, lateral thalamus, posterior IC
  • Basilar
    • paramedian branches >> medial pons
    • These vessels are vulnerable to rupture during uncal herniation, producing Duret haemorrhages
  • Anterior cerebral (ACA)
    • recurrent artery of Heubner >> caudate, anterior lentiform nucleus, anterior IC
  • ACA & Middle cerebral (MCA)
    • Lenticulostriate branches
  • Posterior cerebral (PCA)
    • thalamoperforant branches

Where is the lesion? (rough guide)

Pure motor Internal capsule / corona radiata
Sensori-motor PL thalamus & internal capsule
Pure sensory PL thalamus
Ataxic hemiparesis Internal capsule / corona radiata, basal pons, thalamus
Dysarthria-clumsy hand Basal pons / internal capsule

Presenting complaint

  • No cortical signs (aphasia, hemianopia, apraxia etc.)
  • Associated subcortical signs (coma, seizures)
  • Classic syndromes:
    • Pure motor hemiparesis (>45%)
    • Sensorimotor stroke (15-20%)
    • Pure sensory stroke (7-18%)
    • Ataxic hemiparesis (3-18%)
    • Dysarthria-clumsy hand syndrome (<6%)

Imaging

Left thalamic lacunar infarct – non-contrast CT. Taken from Radiopaedia

Right thalamic lacunar infarct – MRI DWI. Taken from Radiopaedia