<s>[INST] context: The Romberg is a test of proprioceptive function: The Romberg test explores for imbalance due to proprioceptive sensory loss. The patient is able to stand with feet together and eyes open but sways or falls with eyes closed; it is one of the earliest signs of posterior column disease. - DeJong's the neurologic examination Proprioceptive pathway: Proprioception is the ability to sense the position of one's extremities without the aid of vision. The peripheral sense organs are located in the muscle, tendons, and joints. The first cell body is situated in the dorsal root ganglion, going without a synapse to the ipsilateral fasiculi cuneatus and gracilis (dorsal column) to the lower medulla where the synapse occurs. Following a decussation of the internal arcuate fibers, the impulses ascend in the medial leminiscus to the thalmus, terminating in the parietal lobe, posterior to those that convey touch. Patholophysiologic basis of Romberg test: Central postural control (equilibrium) is dependent on input from three peripheral modalities: Joint position sense (proprioception), carried in the dorsal columns of the spinal cord; Vision Vestibular apparatus Disturbance in any one of these modalities can be compensated for (completely or incompletely) by input from the other two systems. Impaired proprioception can be over come by visual and vestibular feedback. However, reduced visual input in the dark surroundings or due to failing vision can seriously predispose such a patient to severe incoordination (ataxial) Asking the patient to close his eyes during rombergs test helps uncover any disordered proprioception that may have been masked by vision. Conditions commonly causing a positive Romberg test: Posterior column dysfunction Posterior cord compression Multiple sclerosis Subacute combined degeneration of the spinal cord Tabes dorsalis Sensory polyneuropathy Idiopathic Diabetes mellitus Intracranial lesions Less common Romberg's test is not a test of cerebellar function. Patients with cerebellar ataxia will, generally, be unable to balance even with the eyes open. [/INST] question: Semicircular canal involved in Positive Romberg test with eyes closed detects defect in: | options: A: Proprioceptive pathway B: Cerebellum C: Spinothalmic tract D: Peripheral nerve | answer: A </s>