A lesion of the dorsal columns at the level of the cervical spine results in loss of which sensory modalities below the level of injury on the ipsilateral side?

Explanation

## Dorsal Column Sensory Loss: Ipsilateral Pattern **Key Point:** The dorsal columns (fasciculus gracilis and cuneatus) are ipsilateral pathways that ascend on the same side of the spinal cord before decussating in the medulla. A dorsal column lesion therefore produces ipsilateral sensory loss below the injury level. ### Sensory Modalities Carried by Dorsal Columns 1. **Fine (discriminative) touch** — ability to distinguish two-point discrimination 2. **Vibration sense** — detected by pacinian corpuscles 3. **Proprioception** — joint position sense and kinesthesia ### Why NOT Pain and Temperature? - Pain and temperature are carried by the **spinothalamic tract**, which decussates within 1–2 spinal segments - A dorsal column lesion spares the spinothalamic tract, so pain and temperature sensation remain intact ### Comparison: Dorsal Columns vs. Spinothalamic Tract | Feature | Dorsal Columns | Spinothalamic Tract | | --- | --- | --- | | **Sensations** | Fine touch, vibration, proprioception | Pain, temperature, crude touch | | **Crossing level** | Medulla (via internal arcuate fibres) | 1–2 spinal segments | | **Loss pattern with lesion** | Ipsilateral below lesion | Contralateral below lesion | | **Dorsal column syndrome** | Loss of fine touch & proprioception | Preserved pain/temperature | **High-Yield:** **Dorsal Column Syndrome** (e.g., from vitamin B₁₂ deficiency, tabes dorsalis, or multiple sclerosis) classically presents with loss of vibration and proprioception with preserved pain sensation — the opposite of spinothalamic lesions. **Mnemonic:** **DCFVP** = **Dorsal Columns = Fine touch, Vibration, Proprioception** (ipsilateral loss). **Clinical Pearl:** In **Brown-Séquard syndrome** (hemisection of spinal cord), dorsal column damage on the injured side produces ipsilateral loss of fine touch and proprioception, while contralateral spinothalamic damage produces loss of pain and temperature sensation — a dissociated sensory loss pattern.