A 28-year-old male presents to the emergency department 2 hours after a motorcycle collision with hyperextension injury to the cervical spine. On examination, he has intact motor function in the upper and lower extremities bilaterally, but complete loss of pain and temperature sensation below the C5 dermatome on the right side, with preserved crude touch and proprioception. The left side shows normal sensation throughout. MRI reveals a central cord contusion without fracture. Which spinal cord syndrome best describes this clinical presentation?

Explanation

## Clinical Diagnosis: Brown-Séquard Syndrome ### Key Presentation Features **Key Point:** Brown-Séquard syndrome results from hemisection (half-section) of the spinal cord, classically producing ipsilateral motor loss and ipsilateral loss of proprioception/vibration, with **contralateral** loss of pain and temperature sensation (2–3 levels below the lesion). However, in this vignette the patient demonstrates a **partial/incomplete Brown-Séquard pattern**: - **Intact motor function bilaterally** (incomplete hemisection sparing corticospinal tracts) - **Right-sided loss of pain and temperature** below C5 (ipsilateral spinothalamic involvement — consistent with a right-sided cord lesion where the spinothalamic fibers have already crossed) - **Preserved crude touch and proprioception** (dorsal columns intact) - **Normal left-sided sensation throughout** - MRI: central cord contusion without fracture The **unilateral (right-sided only)** loss of pain and temperature with preservation of all other modalities and normal contralateral sensation is the hallmark of a Brown-Séquard or Brown-Séquard–plus syndrome (incomplete hemisection). ### Anatomical Basis **High-Yield:** The spinothalamic tract (pain and temperature) crosses within 1–2 spinal segments of entry and then ascends contralaterally. A right-sided cord lesion damages the **already-crossed** left-originating fibers AND the **right-sided** spinothalamic fibers that have not yet crossed, but in a pure hemisection the dominant finding is **ipsilateral** loss of pain/temperature at the level of injury and **contralateral** loss below — or, in incomplete lesions, simply unilateral sensory dissociation as seen here. The dorsal columns (proprioception, vibration, fine touch) and corticospinal tracts run ipsilaterally and are spared in this case. ### Why Not Central Cord Syndrome? **Clinical Pearl:** Central cord syndrome (CCS) produces **bilateral** motor and sensory deficits with upper extremity > lower extremity motor loss. The defining feature of CCS is **bilateral** involvement. This patient has strictly **unilateral** (right-sided) sensory loss with no motor deficit — this pattern cannot be explained by a central lesion, which would affect crossing fibers from both sides symmetrically. ### Differential Comparison | Syndrome | Motor Loss | Pain/Temp Loss | Touch/Proprioception | Laterality | |---|---|---|---|---| | **Brown-Séquard** | Ipsilateral (or absent in incomplete) | Ipsilateral/contralateral dissociation | Ipsilateral loss (or preserved) | **Unilateral** | | Central Cord | Upper > lower, bilateral | Bilateral, central | Preserved | Bilateral | | Anterior Cord | Bilateral motor | Bilateral pain/temp | Preserved | Bilateral | | Posterior Cord | Preserved | Preserved | Bilateral loss | Bilateral | [cite: Greenberg's Handbook of Neurosurgery 9e; Kirshblum SC et al., J Spinal Cord Med 2011; Campbell's Operative Orthopaedics 13e Ch 42]