Which cranial nerves structures receive unilateral innervation from the motor cortex via the corticobulbar tract?

Correct answers are B) Cranial Nerve VII (Facial) - lower part of the nucleus and D) Cranial Nerve XII (Hypoglossal). The corticobulbar tract is responsible for conveying motor signals from the cerebral cortex to the motor nuclei of several cranial nerves. For Cranial Nerve VII (Facial), the innervation is predominantly contralateral in the lower part of the facial nucleus. In the case of Cranial Nerve XII (Hypoglossal), the innervation is also contralateral, affecting the muscles of the tongue. Understanding the unilateral innervation of the lower part of the facial nucleus and the hypoglossal nucleus is crucial in the neurological assessment of facial and tongue weakness. In the context of a unilateral upper motor neuron lesion affecting the corticobulbar tract, there can be weakness or deviation of the lower face muscles on the contralateral side (Facial nerve) and weakness or deviation of the tongue toward the affected side (Hypoglossal nerve). This contralateral innervation pattern is essential to consider in the neurological examination and assessment of conditions affecting these cranial nerves.