Date post: | 24-May-2015 |
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Neuro-clinics 24
Dr Pratyush Chaudhuri
The Spinal Accessory nerve - XI nerve
• It is called accessory because it is accessory to Vagus.
• Two components: 1.cranial part (ramus internus)2.Spinal part (ramus internus)
• Eleventh nerve is entirely motor in function.
• Some element of proprioception
• We cannot assess the accessory segment independantly – along with vagus
• Supplies two muscles
1.Sternocliedomastoid2.Trapezius (upper portion)
• Action of sternocliedomastoid
Turns the head in the opposite direction and upwards.
• Action of trapezius
1. Retracts the head and draws it to the corresponding side
2. Retracts and rotates the scapula – assists in abduction at the shoulder.
• When both sternocliedomastoid work together – causes flexion of the cervical spine + brings the head forward and downward.
• When both trapezius work together – head is drawn backwards and face is deviated upwards.
• Accessory nerve connects closely with the medial longitudinal fasciculus (MLF)
This is responsible for oculo-cephalic reflex (dolls eye reflex)
Clinical examination
Sternocliedomastoid • Observe : muscle bulk, tone at rest and on
movement• Active examination – movement against
resistance.• Sternocleidomastoid reflex
Trapezius examination
• Ask patient to shrug and retract the shoulder• Head tilting towards the side is affected.• Finds difficulty in elevating the arm above the rt
shoulder.
Lesions
Supranuclear• Since central regulation is bilat- deficit expressed less
Paralytic• Notable as shoulder depression (often resulting in
painful shoulder in hemiplegics)
Irritative – supra nuclear
• More common• Results in head turning with deviation of the eye in
seizures
Dissociative paralysis• Trap on one side and sternocleidomastoid on the
other side: happens with lesions above the third nerve nuclei ipsilateral to the sterno.
Extra-pyramidal lesions: Oculogyric crisis
• Nuclear palsy
• Rare- may occur with pseudo-bulbar palsy
• Note the presence of atrophy and fasciculations
Infra-nuclear• Cervical adenitis• Meningitis• Neoplasms• Trauma, skull base fractures, cervical spine injuries.
Notable weakness and wasting
Torticollis (Wryneck)
• Abnormal function of the inhibitory inter-neural network between the trigeminal and accessory has been suggested.
• By far lateral but retrocollis and anterocollis is known
Etiology
Congenital• Hypertrophy, congenital fusion of the cervical
vertebrae, Klippel-feil syndrome, spina bifidaAcquired• Neonatal: trauma to the sterno at birth.• Post traumatic• Infection – meningitis, cervical adenitis• Reflex torticollis: secondary to occipital neuralgia
Drug induced• Classical phenothiazines, metclopropamide
Neurogenic: Post encephalitic and dystonias
Psychogenic torticollis
That all for today ….
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