bulbar

Bulbar is an adjective used in medicine and anatomy, derived from the Latin bulbus, meaning a bulb. In neuroanatomy, bulbar refers to the bulbar region of the brainstem, especially the medulla oblongata, where several cranial nerve motor nuclei reside. The bulbar region includes the nuclei of cranial nerves IX (glossopharyngeal), X (vagus), XI (accessory), and XII (hypoglossal), and is involved in speech, swallowing, and palate movements.

Clinical involvement of the bulbar region typically produces bulbar signs such as dysarthria (slurred or nasal speech), dysphagia (swallowing difficulty), tongue weakness with fasciculations, facial weakness, and altered gag reflex. Bulbar palsy denotes a lower motor neuron syndrome affecting bulbar muscles due to degeneration or damage of the bulbar nuclei or their fiber tracts, seen in conditions such as amyotrophic lateral sclerosis, brainstem stroke, or poliomyelitis.

Pseudobulbar palsy refers to bilateral upper motor neuron lesions affecting corticobulbar pathways, resulting in spastic dysarthria, dysphagia, and emotional lability.

In ophthalmology, bulbar can describe bulbar conjunctiva, the portion of the conjunctiva that covers the visible sclera of the eyeball, as opposed to the palpebral conjunctiva on the eyelids.

Etymology traces to Latin bulbus, bulb, reflecting the historical notion of a bulb-like region in the brainstem.