Glossopharyngeal (IX) and vagus (X) lesions - Disorders of cranial nerves

Glossopharyngeal (IX) and vagus (X) lesions

Anatomy

Nerve fibres arise from nuclei in the medulla to form these two nerves, which pass out via the jugular foramen.

Function

They have motor, sensory and autonomic functions. Glossopharyngeal receives taste and common sensation from the posterior third of the tongue, the oropharynx via the pharyngeal plexus, and the tonsillar fossa and soft palate.

Vagus carries motor fibres to the muscles of the palate, pharnyx and larynx. It also carries autonomic innervation to the heart, respiratory tract and gut.

Specific causes

Central causes include vascular lesions of the medulla, tumours, syringobulbia and motor neurone disease. Aneurysms and tumours in the posterior fossa and meningitis may affect the nerves. The left recurrent laryngeal nerve (a branch of the vagus) may be damaged in head and neck surgery, or compressed by hilar lymph nodes from lung tumours.

Clinical features

Impaired gag reflex (IX forms the sensory component, X the motor), a hoarse voice and abnormal swallow.