An 88-year-old patient presents with right-sided weakness after a fall. What is the most likely diagnosis?

In this scenario, the most appropriate diagnosis for an 88-year-old patient presenting with right-sided weakness after a fall is a left-sided stroke. The reason for this is based on the principles of neuroanatomy and the fact that motor function is typically contralateral; that is, a problem in one hemisphere of the brain affects function on the opposite side of the body.

When a patient exhibits weakness on the right side, it suggests there may be issues in the left hemisphere of the brain, which controls the right side of the body. Strokes can result from various conditions, such as obstruction of blood flow (ischemic stroke) or bleeding (hemorrhagic stroke).

Furthermore, considering the age of the patient, strokes become more prevalent, and the occurrence of sudden weakness following a fall is characteristic of a cerebrovascular event. A transient ischemic attack (TIA) could also present with similar symptoms, but TIAs are usually temporary and resolve quickly, while in this case, the persistence of right-sided weakness would indicate a more definitive cerebrovascular accident such as a stroke.

In conclusion, the left-sided stroke is the most likely diagnosis in this case due to the presentation of right-sided weakness following a fall in an elderly patient.