Cranial Nerves

Nerves that extend throughout the body on both sides emerging directly from brain and brain stem are called Cranial nerves. These nerves carry information from brain to all parts of the body, primarily to the head and neck. These nerves are paired and present on both sides of the body. They are primarily responsible for facilitating smell, vision, hearing, and movement of muscles.

Traditionally, there are twelve cranial nerves which are numbered using Roman numerals according to the order in which they emerge from brain (from front to back).

Cranial nerves are considered as a part of the peripheral nervous system, although olfactory and optic nerves are considered to be part of the Central nervous system.

 Cranial Nerves

List of Cranial nerves, location, and its functions

Cranial nerves are basically named corresponding to their structure and functions. Olfactory and optic nerves emerge from cerebrum and all other 10 nerves emerge from the brain stem. Cranial nerve functions include all five senses and muscle movements. Here is the detailed list of Cranial nerves and their functions.

Number Name Location  Function
I Olfactory Cribriform plate Smell
II Optic Optic foramen Vision
III Oculomotor Superior orbital fissure Eye movement
IV Trochlear Superior orbital fissure Eye movement
V Trigeminal Superior orbital fissure Facial sensation
VI Abducens Superior orbital fissure Eye movement
VII Facial Internal auditory canal Facial expression
VIII Vestibulocochlear Internal auditory canal Hearing and balance
IX Glossopharyngeal Jugular foramen Oral sensation and taste
X Vagus Jugular foramen Vagus nerve
XI Accessory Jugular foramen Shoulder elevation and head turning
XII Hypoglossal Hypoglossal Tongue movement

Functions of Cranial Nerves

Olfactory nerve:  This nerve helps to feel the sense of smell. This is the primary nerve that is responsible for smell.Damage to this nerve may result in distortion of smell and taste.

Optic nerve: Optic nerve is the agent of vision. This transmits visual information for eyes to the brain and vice versa. Any damage to this nerve results in problems related to sight and vision.

Oculomotor nerve: Oculomotor nerve helps in the movement of the eye. Damage to this nerve leads to distortion in vision or double vision and even problem in the coordination of eyes.

Trochlear and Abducens nerves: These nerves also help in eye movement. Damage to the Trochlear nerve might cause inability to move eyeball downwards and damage to Abducens might result in diplopia.

Trigeminal nerve: This nerve helps you to have facial sensation. This nerve comprises of three parts namely ophthalmic, maxillary and mandibular.

Facial nerve: This nerve is responsible for facial expression.Due to the damage to this nerve, it might cause inability to move face parts on one or more sides.

Vestibulocochlear: Vestibulocochlear is responsible for hearing and balance. This helps eyes to keep track of moving objects while your head is stable. The sensation of spinning and dizziness are the symptoms of damage to this nerve.

Glossopharyngeal: Oral sensation and taste are stimulated by this nerve. Damage to this nerve leads to the inability to recognize taste and so on.

Vagus nerve:  This nerve monitors the level of oxygen and helps us to feel the sensation of heat or cold near throat area. Damage to this nerve leads to the inability to swallow. Major damage to vagus nerve might result in Hypertension or high blood pressure and heart attack.

Accessory nerve: This nerve arises from two roots namely the cranial and spinal ones. This nerve controls swallowing movements and helps in the movement of head and shoulders.

Hypoglossal nerve: This nerve facilitates the movement of the tongue and helps to talk, swallowing etc.

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