Abducent Nerve
The structure indicated is the
abducent nerve (cranial nerve VI). The abducent nerve (cranial nerve VI), provides
general somatic efferent fibres (motor function) to the
lateral rectus muscle of the eye. There are three cranial nerves which are responsible for innervating the extrinsic muscles of the eye:
- Oculomotor nerve (cranial nerve III)
- Trochlear nerve (cranial nerve VI)
- Abducent nerve
The
oculomotor nerve supplies the
superior, inferior and
medial rectus muscles, as well as the
inferior oblique muscle and the
levator palpebrae superioris.
The
trochlear nerve supplies the
superior oblique muscle.
It originates between the
pons and the
medulla of the brain stem. It has a long intracranial course which makes it vulnerable to injury: fractures of the petrous part of the temporal bone, aneurysms of the internal carotid artery and mass lesions all put this nerve at risk. Lesions of the abducent nerve cause diplopia on lateral gaze, with inability to abduct the affected eye – the eye is pulled medially due to the unopposed action of the medial rectus muscle.
Learn more about the cranial nerves in this
anatomy tutorial
