What condition is characterized by bilateral loss of vibration and proprioception with preserved motor function?

Posterior cord syndrome is characterized by the loss of vibration and proprioception sensation while motor function is preserved. This condition results from damage to the posterior columns of the spinal cord, which are responsible for conveying proprioceptive and vibratory information from the periphery to the brain. Patients with posterior cord syndrome typically present with a "bag of marbles" sensation in their feet, where they can sense movement but not the position of their limb or the vibration.

In this condition, the pathways for motor function (such as the corticospinal tract) remain intact, allowing for preserved muscle strength and movement abilities despite the loss of sensory modalities. This distinguishes it from other syndromes, such as anterior cord syndrome, where motor function is impaired, and central cord syndrome, which generally presents with greater weakness in the upper extremities compared to lower extremities. Brown-Séquard syndrome is characterized by hemisection of the spinal cord, resulting in ipsilateral motor loss and contralateral sensory loss.