What are the typical presentations of a unilateral lesion in the pons?

A unilateral lesion in the pons typically affects both motor and sensory pathways. The correct presentation comprises contralateral hemiparesis (weakness of one side of the body) and ipsilateral facial palsy (weakness of the facial muscles on the same side as the lesion). This occurs due to the anatomy of the brainstem and its pathways: motor fibers that originate in the cortex cross over at the level of the medulla, thus affecting the opposite side of the body, while nuclei responsible for facial movements (such as the facial nerve) are located in the pons and control muscles of the same side of the face.

In this context, the first key point to understand is how these structures are arranged. A lesion affecting the pons damages the facial nucleus, resulting in facial weakness on the same side (ipsilateral), while the descending motor pathways that travel down from the cortex have already crossed, leading to weakness on the opposite side (contralateral hemiparesis).

The other choices describe presentations that either do not align with this anatomy or showcase symptoms that would not be consistent with a unilateral pontine lesion. For instance, contralateral facial palsy does not occur because facial nerve function is localized to the same side as the