abducens


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abducens

[ab′dyü·sənz]
(neuroscience)
The sixth cranial nerve in vertebrates; a paired, somatic motor nerve arising from the floor of the fourth ventricle of the brain and supplying the lateral rectus eye muscles.
References in periodicals archive ?
The trochlear nuclei in the lower midbrain and abducens nuclei in the pons are the origins of the 4th and 6th cranial nerves innervating, respectively, the superior oblique (SO) and lateral rectus (LR) muscles.
The abducens nuclei occupy a posterior position close to, but not at, the midline of the middle-to-caudal pons (Figure 5), separated from the floor of the 4th ventricle by axon fascicles of the main facial (7th cranial) nerves which bend around them forming paired posterior surface swellings at this pontine level (the facial colliculi).
The abducens nucleus, located in the pons, is of central importance in the control of horizontal gaze as it governs conjugate movements of both the ipsilateral lateral rectus and contralateral medial rectus muscles (Fig 3).
Cranial nerve involvement is usually limited to the vestibulocochlear and facial nerves, but trigeminal and abducens nerve palsies have also been reported.
The ocular palsies associated with this syndrome are attributed to lesions affecting the abducens nuclei and other eye movement centres in the pens and midbrain.
They bend around the abducens nucleus to form the first genu of the facial nerve.
Diabetic patients presenting to an optometrist with diplopia may have a mononeuropathy of the oculomotor (3rd), trochlear (4th) or abducens (6th) cranial nerve.
This article describes a case of one such complication--sigmoid sinus thrombosis--that was manifested by a contralateral abducens palsy.
The most common ophthalmoplegias are caused by oculomotor (III) and trochlear (IV) nerve palsies; abducens (VI) palsies are the least common.
Unlike Manlapaz, [6] we found no case of abducens nerve palsy in our patients.
It also seems fair to state that antibiotics are a mixed blessing in that the cardinal symptoms of petrous apicitis--deep retrobulbar pain and abducens paralysis with otomastoiditis (Gradenigo's syndrome)--are rarely present these days, which often contributes to a delayed diagnosis.
Original indications for MRI in the 88 patients Signs n Symptoms n [*] None 75 Headache 61 Trismus 5 Facial pain 15 Decreased facial 5 Orbital pain 7 sensitivity Tinnitus 4 Serous effusion 1 Facial numbness 1 Abducens palsy 1 Hearing loss 1 Nasopharyngeal mass 1 Doplopia 1 (*.