Abducens Nerve

Human anatomy > Peripheral Nervous System > Abducens Nerve

The nervous system is divided into two parts: the central nervous system and the peripheral nervous system. The peripheral nervous system is further subdivided into the autonomic nervous system and the sensory-somatic nervous system.

The sensory-somatic system consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves. The sixth pair among these 12 pairs is the abducens nerves.

Anatomy books sometimes refer to the Abducens nerve as the “abducent nerve” or simply “abducens.” The abducens nerve innervates and controls the lateral rectus muscle of the eye. The lateral rectus muscle of the eye abducts the eye. This means that the muscle turns the eye outward.

Where can you find the abducens nerve?

There are two abducens nerves in the body, one for each eye. This pair is the sixth of the cranial nerves and it is composed of motor fibers. It leaves the brainstem at the junction of the medulla and pons. It is located medial to the facial nerve. For it to reach the eye, it runs upward and then bends forward.

Abducens nerve

How does the nerve work?

After emerging from the brainstem, the nerve enters the subarachnoid space. Damage to the length of the nerve between the brainstem and the eye may cause detrimental effects. Fractures of the petrous temporal bone, aneurysms of the intracavernous artery or mass lesions that push the brainstem downward can cause damage to the abducens nerve.  

Any damage to the nerve or any dysfunction of the nerve may cause sixth nerve palsy or abducens nerve palsy. Sixth nerve palsy is a very common disorder that may affect one side/eye (unilateral abducens nerve palsy) or both sides/eyes (bilateral abducens nerve palsy). A person with this disorder has an inability to turn the eye outward. A patient with this inability suffers from convergent strabismus or esotropia. Double vision or diplopia characterizes strabismus or esotropia (i.e. two images appear side-by-side).

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