SPPA 2050 Speech Anatomy & Physiology

Summary of cranial nerves relevant for speech production.

Number / Name / Nerve type / Basic function / Detailed function
I / Olfactory / Sensory / Smell / -
II / Optic / Sensory / Vision / -
III / Oculomotor / Motor / Eye movement / -
IV / Trochlear / Motor / Eye movement / -
V / Trigeminal / Mixed / Speech / -Largest cranial nerve whose name (TRIgeminal) implies three parts or branches.
-Opthalmic branch carries sensation from the upper face, eye and ventral scalp.
-Maxillary branch carries sensation from the mid-face, upper mouth, upper gums and teeth and palate.
-Mandibular branch carries sensation from the lower face region, skin of ear, lower teeth and gums and mucous membrane of the anterior 2/3 of tongue. This branch provides motor supply to the lower jaw muscles.
VI / Abducens / Motor / Eye movement / -
VII / Facial / Mixed / Speech / -Carries sensation of taste from the anterior 2/3 of tongue.
-Provides motor supply to the muscles of facial expression (including the lips), posterior belly of digastric, stylohyoid and the stapedius muscle in middle ear.
-Damage to the facial nerve can result in a complex of symptoms called Bell’s palsy, which includes an immobile face (on the affected side).
-Contains autonomic fibers.
VIII / Auditory (Vestibulococchlear) / Sensory / Hearing / -Carries sensation of hearing and balance.
IX / Glossopharyngeal / Mixed /

Speech

/ -Carries general sensation and taste from the posterior 1/3 of the tongue.
-Provides motor supply to stylopharyngeus and the pharyngeal constrictor muscles via the pharyngeal plexus.
-Contains autonomic fibers.
X / Vagus / Mixed / Speech / -Very large and important nerve wanders through the neck, thorax and abdomen.
-Has a number of branches.
-Pharyngeal branch (or nerve) carries sensation from the pharynx and soft palate and provides motor supply to the muscles of the soft palate and pharynx.
-Superior laryngeal branch (or nerve) has an external branch provides motor supply to part of the pharynx and a single muscle in the larynx, the cricothyroid, which aids in vocal pitch adjustment, and an internal branch which carries general and taste sensation from the base of the tongue and rostral part of the larynx.
-Recurrent laryngeal branch (or nerve) carries sensation from the caudal portion of the larynx and provides the motor supply to all “intrinsic” muscles of the larynx (except cricothyroid). This nerve is named “recurrent” because it travels down into the thorax and then returns to the neck.
-Contains a large number of autonomic fibers that supply many internal organs.
XI / (Spinal) Accessory / Motor / Speech / -Provides motor supply to muscles of the neck, pharynx and palate (?).
XII / Hypoglossal / Motor / Speech / -Provides motor supply to the muscles of the tongue except for palatoglossus