Final answer:
A 56-year-old male with a C5-C8 cervical cord infarction would most likely retain normal lower extremity reflexes due to the lesion's location. Upper motor neuron lesion symptoms may present in the upper limbs, while lower extremities are generally unaffected. Sensory deficits in a hemisection of the spinal cord would include loss of fine touch and proprioception on the affected side while preserving pain sensation.
Step-by-step explanation:
A 56-year-old male with a C5-C8 cervical cord infarction would most likely have normal lower extremity reflexes. Considering that the lesion is in the cervical spine, it would mainly affect the nerve pathways that innervate the upper limbs, leading to potential upper extremity deficits. Thus, reflexes tested in the lower extremities, which are governed by spinal cord segments below the level of the infarction, should remain normal.
In the context of a cervical cord infarction, an upper motor neuron (UMN) lesion can be inferred since the cervical spinal cord portion primarily contains UMNs that originate from the cerebral cortex and descend to control the spinal motor neurons. Symptoms of an UMN lesion include muscle weakness, strong deep tendon reflexes, spasticity, and a positive Babinski reflex. However, touch and vibration sensations might be preserved since they are conveyed through different pathways, namely the dorsal columns, which may not be affected by the infarct.
For the scenario provided in question 29, where a victim loses the ability to move the right leg but retains normal control over the left one, it suggests damage to the lateral corticospinal tract on the paralyzed side. The sensory deficits expected would be a loss of fine touch and proprioceptive sensations on the same side of the hemisection due to damage to the dorsal column pathway which ascends ipsilaterally. Pain sensations, which travel via the spinothalamic pathway, would remain intact because this pathway decussates or crosses over the midline soon after entering the spinal cord and therefore bypasses the hemisection.