A patient with chronic back pain has abnormalities of proprioception and vibration discrimination. Which part of the spinal column is likely affected?

The correct choice is associated with abnormalities of proprioception and vibration discrimination due to the specific functions of the posterior column in the spinal cord. The posterior columns, which include the fasciculus cuneatus and fasciculus gracilis, are responsible for conveying fine touch, proprioception, and vibrational sensations from the body to the brain. When these pathways are affected, patients typically present with difficulties in these sensory modalities, which can manifest as altered perception of body positioning (proprioception) and the ability to perceive vibrating stimuli.

The other options relate to different pathways and functions. The lateral spinothalamic tract primarily transmits pain and temperature sensations, while the ventral spinothalamic tract transmits crude touch and pressure sensations. Transection of the cord would result in a more generalized loss of sensory and motor function below the level of injury, but it does not specifically target the recognition of proprioception and vibration. Therefore, the correct identification of the posterior column aligns directly with the sensory deficits exhibited by the patient.