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Oxford University Press makes no representation, express or implied, that the drug dosages in this book are correct. Readers must therefore always … More Oxford University Press makes no representation, express or implied, that the drug dosages in this book are correct. Readers must therefore always check the product information and clinical procedures with the most up to date published product information and data sheets provided by the manufacturers and the most recent codes of conduct and safety regulations. The authors and the publishers do not accept responsibility or legal liability for any errors in the text or for the misuse or misapplication of material in this work. Except where otherwise stated, drug dosages and recommendations are for the non-pregnant adult who is not breastfeeding. You do not currently have access to this chapter. The oculomotor nerve is the third cranial nerve (CN III). It enables eye movements, such as focusing on an object that’s in motion. Cranial nerve III also makes it possible to move your eyes up, down and side to side.
OverviewWhat is the oculomotor nerve?The oculomotor nerve is one of 12 sets of cranial nerves. Many of these nerves are part of the autonomic nervous system. The autonomic nervous system supplies (innervates) organs, like your eyes. The oculomotor nerve is the third cranial nerve (CN III). It allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the position of the upper eyelid. Cranial nerve III works with other cranial nerves to control eye movements and support sensory functioning.
FunctionWhat is the function of the oculomotor nerve?It controls four of the six muscles that enable eye movement. CN III makes it possible to:
How does CN III work?It coordinates eye movement with motions that include:
AnatomyWhat is the anatomy of cranial nerve III?CN III starts in the midbrain. It travels through many structures in your head until it reaches the back of your eyes. Its course includes:
The superior and inferior branches connect to four of the muscles that control eye movements, as well as an upper eyelid muscle and muscles inside the eye that control pupil size and focusing of the lens. These include the:
Conditions and DisordersWhat conditions can affect the oculomotor nerve?Oculomotor dysfunction is a group of disorders affecting CN III. These disorders are also known as third nerve palsy. They occur when cranial nerve III becomes paralyzed. Third nerve palsy can be present at birth. It may also occur later in life due to:
Conditions that may cause oculomotor dysfunction include:
CareHow can I prevent oculomotor nerve dysfunction?It might not be possible to prevent certain conditions that affect CN III. For example, complications from neurological disease or tumors may be unavoidable. Preventive measures that are within your control include:
What can be done to correct a third nerve palsy?Treatment for third nerve palsy depends on what caused it. There is no treatment to reestablish function of a congenital third nerve palsy. An acquired third nerve palsy may resolve on its own, depending on the cause. If a brain tumor or aneurysm is causing the third nerve palsy, surgery to relieve pressure on the third nerve may help it function. An ophthalmologist will wait at least 6 months after onset of third nerve palsy to see if it gets better on its own. During this time, an eye patch or prism glasses may help you with double vision. Eye muscle surgery (strabismus surgery) may help to realign the eyes so that the eyes are straight when looking straight ahead. But it can sometimes take numerous procedures. People typically still experience double vision when looking to the sides after strabismus surgery. Frequently Asked QuestionsWhen should I call a healthcare provider about concerns with cranial nerve III?Contact your healthcare provider if you experience symptoms of third nerve palsy. These include:
A note from Cleveland Clinic The oculomotor nerve is the third cranial nerve. It controls four of the six muscles that enable eye movement. Conditions affecting cranial nerve III include third nerve palsy. It is often a complication of medical issues such as uncontrolled diabetes or a brain aneurysm. Third nerve palsy might impact your vision and the appearance of one or both of your eyes. Many people make a full recovery, although it can take around two months. Get useful, helpful and relevant health + wellness information
 enews More health news + infoWhat cranial nerves are involved in corneal reflex?The corneal reflex uses cranial nerve V as its afferent loop and cranial nerve VII as its efferent loop.
Which cranial nerve has both sensory and motor functions?The trigeminal nerve is the largest of your cranial nerves and has both sensory and motor functions. The trigeminal nerve has three divisions, which are: Ophthalmic. The ophthalmic division sends sensory information from the upper part of your face, including your forehead, scalp, and upper eyelids.
Which cranial nerves affect blinking?The afferent limb of the blink reflex is mediated by sensory fibers of the supraorbital branch of the ophthalmic division of the trigeminal nerve (cranial nerve V1) and the efferent limb by motor fibers of the facial nerve (cranial nerve VII).
Which 3 cranial nerves are purely motor for the eye?Four cranial nerves are purely motor–the 3rd, 4th, 6th, and 12th. Cranial nerve 3 is called the oculomotor. It supplies four of the six muscles that move the eye. It also supplies the eyelid raising muscle and the muscles that focus the lens and constrict the pupil.
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What cranial nerves are involved in the sensory and the motor roles for the corneal blink reflex?
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