A 70-year-old man writes fluently but cannot read his own handwriting aloud, although he names objects placed in his left hand correctly. He has a right homonymous hemianopia. Which combination of lesions explains this picture?

• A Infarction of the left superior longitudinal fasciculus
• B Infarction of the left angular gyrus alone
• C Infarction of the left visual cortex together with the splenium of the corpus callosum ✓
• D Infarction of the right occipital cortex and right splenium

Explanation

Alexia without agraphia follows left posterior cerebral artery infarction damaging the left visual cortex and the splenial fibres crossing from the right visual cortex. Visual input reaches language areas only from the left field via intact left cortex, while written material seen by the right cortex cannot cross the damaged splenium, so reading is lost despite intact writing. An angular gyrus lesion produces alexia WITH agraphia, and the arcuate fasciculus lesion gives conduction aphasia with impaired repetition.

Reference: Snell's Clinical Neuroanatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.