Neuro clinics 24 - spinal accessory

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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