**Question:** The following are Components of Brown-Séquard syndrome except

A. Loss of sensitivity to pinprick and light touch on one side of the body
B. Loss of proprioception
C. Decreased deep tendon reflexes
D. Spasticity

**Core Concept:**
Brown-Séquard syndrome is a disorder resulting from unilateral spinal cord injury. It is characterized by the loss of sensitivity to pinprick and light touch on one side of the body (paraplegic side), loss of proprioception, and decreased deep tendon reflexes. The injury typically affects the anterior horn cells and the posterior columns of the spinal cord, leading to these symptoms.

**Why the Correct Answer is Right:**
Option D (spasticity) is not a component of Brown-Séquard syndrome because spasticity is a motor disorder characterized by increased tone and hyperreflexia, which is not a consequence of spinal cord injury affecting primarily sensory and proprioceptive pathways.

**Why Each Wrong Option is Incorrect:**
Option A (decreased deep tendon reflexes) can be present, but it is not a defining feature of Brown-Séquard syndrome. In fact, reflexes are typically increased in this condition due to the spared reflex arc.

Option B (spinal cord injury) is not correct because Brown-Séquard syndrome results from injury to the anterior horn cells and the posterior columns of the spinal cord, leading to the specific symptoms mentioned.

Option C (spinal cord injury) is not correct because the syndrome is characterized by the specific symptoms mentioned, not spinal cord injury in general.

**Clinical Pearl:**
Brown-Séquard syndrome is a useful clinical clue to consider spinal cord injury as a potential cause of certain symptoms, allowing for the appropriate diagnostic workup and management. It is essential to recognize this syndrome to correctly diagnose patients with symptoms that may be misattributed to other causes without this diagnostic clue.