North American Veterinary Licensing Examination (NAVLE) Practice Test

Where is the spinal cord lesion in a dog with specific reflex signs based on the given clinical presentation?

1. L4-S3

2. C1-C5

3. T3-L3

4. C6-T2

The correct answer is: C6-T2

In the context of evaluating spinal cord lesions in a dog based on reflex signs, the correct answer indicates a lesion located in the cervical region, specifically between the C6 and T2 vertebrae. This area is critical because it corresponds to important neural pathways involved in both reflex actions and voluntary movement. A lesion in the C6-T2 region can disrupt the upper motor neuron pathways serving the thoracic limbs, leading to characteristic signs that may include deficits in voluntary movement in the front legs, altered reflexes such as an exaggerated withdrawal reflex, and potentially altered proprioception. The C6-T2 segments are particularly significant for the thoracic limb’s motor function since this is where innervation for the forelimbs originates. Additionally, clinical signs associated with lesions in this region can include an atrophy of shoulder muscles due to disuse, as well as diminished reflexes in the hind limbs depending on the severity and specific location of the lesion. Understanding the location and associated signs is crucial for accurate diagnosis and treatment planning in veterinary practice.