A patient has no sensation below the L2 dermatome after a recent motor vehicle accident. What is the MOST likely rationale for this finding?

• A. The patient has a complete transection of the spinal cord
• B. The patient has a dorsal column lesion within the spinal cord
• C. The patient has a hemisection of the spinal cord
• D. The patient has a spinothalamic tract lesion within the spinal cord

Answer: (A)

When sensory loss extends below a single spinal level across all modalities, it points to a complete transection of the spinal cord at that level. Here, no sensation is felt below the L2 dermatome, indicating that all sensory pathways—pain, temperature, vibration, proprioception, and touch—are interrupted below the level of injury, and motor pathways to the legs are typically affected as well.

Other patterns don’t fit as well: a dorsal column lesion would spare pain and temperature and mainly disrupt fine touch and proprioception; a hemisection would cause a mix of ipsilateral motor/proprioceptive loss with contralateral pain/temperature loss; a spinothalamic tract lesion would mainly disrupt pain and temperature, with other modalities largely preserved on the same side. The widespread loss below L2 best matches a complete spinal cord transection at or around that level.