Which of the following conditions affects the basal ganglia?

Parkinson's disease is a neurodegenerative disorder that primarily affects the basal ganglia, which are a group of structures involved in coordinating movement. In Parkinson's disease, there is a loss of dopaminergic neurons in the substantia nigra, a part of the basal ganglia. This degeneration leads to the characteristic motor symptoms of the condition, such as tremors, rigidity, bradykinesia (slowness of movement), and postural instability. The basal ganglia play a pivotal role in regulating voluntary motor control, and their dysfunction in Parkinson’s disease underscores the significant impact of this condition on movement and coordination.

The other conditions listed do not have a primary impact on the basal ganglia. Bacterial meningitis affects the protective membranes (meninges) covering the brain and spinal cord, leading to inflammation and possibly affecting other brain areas indirectly. Osteomyelitis is an infection of the bone, which does not directly involve the brain's structures. A comminuted fracture refers to a type of bone break where the bone is shattered into multiple pieces and is not related to the basal ganglia's function or structure.