National Board of Chiropractic Examiners (NBCE) Practice Test

Which of these reflexes would most likely be abnormal in a patient with cauda equina syndrome?

1. Cremasteric Reflex

2. Patellar Reflex

3. Biceps Reflex

4. Achilles Reflex

The correct answer is: Cremasteric Reflex

In patients with cauda equina syndrome, the most likely abnormal reflex is the cremasteric reflex. This reflex is primarily mediated by the L1 and L2 spinal nerves, which play a crucial role in the innervation of the cremaster muscle in males. When functioning normally, stimulation of the inner thigh results in the contraction of the cremaster muscle, which elevates the testicle on the same side. Cauda equina syndrome involves damage to the bundle of nerves located at the lower end of the spinal cord, which can lead to neurological deficits that specifically impact lower motor neuron function. The damage to these nerve roots may disrupt the ability to elicit this reflex, resulting in flaccidity or asymmetry, which is a hallmark of the syndrome's clinical presentation. In contrast, reflexes such as the patellar, biceps, and Achilles reflexes are associated with different spinal cord segments and are less likely to be affected in cauda equina syndrome unless the pathology extends significantly upward. Specifically, the patellar reflex is linked to the L2-L4 segments, the biceps reflex to C5-C6, and the Achilles reflex to S1-S2. While all of these may show changes depending on the severity and location of