Corticobulbarura

Corticobulbarura is a term occasionally used to refer to the corticobulbar tract, a major descending motor pathway that connects the cerebral cortex to motor nuclei in the brainstem. It is part of the broader pyramidal motor system and plays a key role in controlling voluntary movements of the face, head, and neck.

Anatomy and pathway

The corticobulbar tract originates mainly from the motor cortex, particularly areas responsible for facial movement, with contributions from adjacent premotor and other cortical regions. Its fibers descend through the internal capsule, travel in the crus cerebri of the midbrain and the basis pontis of the pons, and terminate on the motor nuclei of cranial nerves III, IV, V, VII, IX, X, XI, and XII in the brainstem.

Function

Through these connections, the corticobulbar tract governs voluntary movements of muscles involved in facial expression, mastication, swallowing, phonation, and other head and neck actions. Corticobulbar projections help coordinate speech and swallow, among other functions.

Innervation patterns

Corticobulbar inputs are largely bilateral for most cranial nerve nuclei, meaning both hemispheres contribute to the control of many cranial muscles. An exception is the lower facial muscles and some tongue muscles, which show a stronger contralateral influence.

Clinical significance

Lesions affecting the corticobulbar tract can produce upper motor neuron signs in cranial nerve-innervated muscles, such as spastic weakness or dysarthria. Bilateral corticobulbar disruption can result in pseudobulbar palsy, characterized by emotional lability and dysarthria with exaggerated reflexes. Distinguishing corticobulbar from nuclei-specific cranial nerve lesions is important in clinical assessment.

Note

If encountering the term corticobulbarura, it is often a variant spelling or misspelling of corticobulbar tract; standard references typically use corticobulbar tract.