The Hypoglossal Nerve
The Hypoglossal Nerve The hypoglossal nerve (CN XII) is a purely motor nerve, supplying the tongue. Its cells of origin are in the hypoglossal nuclei. The paired nuclei extend almost…
The Spinal Accessory Nerve
The Spinal Accessory Nerve The spinal accessory (SA) nerve, cranial nerve XI (CN XI), is actually two nerves that run together in a common bundle for a short distance. The…
The Glossopharyngeal and Vagus Nerves
The Glossopharyngeal and Vagus Nerves The glossopharyngeal (CN IX) and vagus (CN X) nerves are intimately related and similar in function. Both have motor and autonomic branches with nuclei of…
The Acoustic (Vestibulocochlear) Nerve
The Acoustic (Vestibulocochlear) Nerve The vestibulocochlear, acoustic, or eighth cranial nerve (CN VIII) has two components, the vestibular and the cochlear, blended into a single trunk. The cochlear portion subserves…
The Facial Nerve
The Facial Nerve The facial, or seventh, cranial nerve (CN VII) has two components: the motor root, which makes up about 70% of the fibers, and the sensory root, which…
The Trigeminal Nerve
The Trigeminal Nerve The trigeminal, or fifth cranial, nerve (CN V) has a large sensory part that innervates the face, teeth, oral and nasal cavities, the scalp back to the…
The Ocular Motor Nerves
The Ocular Motor Nerves The oculomotor, or third cranial nerve (CN III) arises from the oculomotor nuclear complex in the midbrain and conveys motor fibers to extraocular muscles, plus parasympathetic…
The Optic Nerve
The Optic Nerve Optic nerve function is tested by examining the various modalities of vision: the visual acuity, the visual fields (VFs), and special components of vision, such as color…
The Olfactory Nerve
The Olfactory Nerve The olfactory nerve is a sensory nerve with but one function, smell. Only volatile substances soluble in lipids or water are perceived as odors. In true anosmia…
Agnosia, Apraxia, and Related Disorders of Higher Cortical Function
Agnosia, Apraxia, and Related Disorders of Higher Cortical Function Gnosia (Gr. gnosis, knowledge) refers to the higher synthesis of sensory impulses, with resulting perception, appreciation, and recognition of stimuli. Agnosia…
