motor nerve conduction studies - clinical … · motor nerve conduction studies department of...

Genomläst 2003-01-21/meg

MOTOR NERVE CONDUCTION STUDIES

Department of clinical neurophysiology

University Hospital

Uppsala, Sweden

by

Björn Falck, Erik Stålberg and Lena Eriksson

version 16-12-1997

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METHODS FOR MOTOR NERVE CONDUCTION STUDIES

N. MEDIANUS

Position of limb: Patient supine, sitting or reclining. Elbow extended or slightly flexed, forearm

supinated, (palm of the hand facing upward), wrist in a neutral position. Fingers in a neutral, relaxed

position, slightly flexed.

Type of recording electrodes: Surface plate electrodes.

Placement of recording electrode: At the midpoint of a line drawn from the first metacarpo-phalangeal

joint and the insertion of the tendon of m. flexor carpi radialis.

Placement of reference electrode: At the distal interphalangeal joint of the thumb

Type of stimulating electrodes: Surface electrodes on a fixed bar.

Stimulation sites:

Palm

Wrist, 80 mm proximal to the recording electrode (measured obliquely, along the course of the nerve)

Elbow

Upper arm

Supraclavicular region

Anomalies: The Martin - Gruber anomaly occurs in many normal subjects. If a Martin -Gruber

anomaly is present, special techniques are required to measure the conduction velocity.

{HYPERLINK "MCV.DOC#MCSmedianus" \l "MCSmedianus"}N. MEDIANUS, H-reflex

Position of limb: Patient supine, sitting or reclining. Elbow extended or slightly flexed, forearm

supinated.


Placement of recording electrode: Over m. flexor carpi radialis 6-8 cm distal to the medial epicondyle.

Placement of reference electrode: Over the lateral epicondyle.


Stimulation site: Elbow.

N. INTEROSSEUS ANTERIOR

Position of limb: Patient supine, sitting or reclining. Elbow extended or slightly flexed. Forearm

pronated (palm facing downwards).


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Position of recording electrode: In the middle of the ventral side of the forearm 3 cm above the distal

ulnar styloid process.

Position of the reference electrode: Over the lateral side of the metacarpophalangel joint of digit I.


Stimulation site: Elbow. If the two sides will be compared make sure that the distance between the

stimulating cathode and recording electrode is identical.

{HYPERLINK \l "MCSinterossant"}N. ULNARIS

Position of limb: Patient supine, sitting or reclining. Elbow slightly flexed (15{\symbol SYMBOL \f

"Symbol"} - 30{\symbol SYMBOL \f "Symbol"}). The forearm is rotated outwards, the palm faces

upwards. The fingers are relaxed in a neutral position, slightly flexed.


Position of recording electrode: At the midpoint of a line between the fifth metacarpo-phalangeal joint

and the piriform bone.

Position of reference electrode: On the middle phalanx of digit V.


Stimulation sites:

Wrist, 80 mm proximal to the recording electrode

Middle of forearm. Below elbow, around 10-15 mm distal to the medial epicondylus

Above elbow, around 90-120 mm proximal to medial epicondylus

Axilla


Anomalies: Martin - Gruber anomaly.

{HYPERLINK \l "MCSulnaris"}

N. RADIALIS – { HYPERLINK "RadialisMCV.doc" }Position of limb: Patient supine, sitting or

reclining. Elbow extended, palm facing downward.


Position of recording electrode: Over the middle of m.extensor indicis propri. On the dorsal side of the

forearm 5-7 cm proximal to the ulnar styloid process.

Position of reference electrode: Over the fifth metacarpal bone.


Stimulation sites:

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Forearm. At the junction of the proximal and middle third of the forearm, in the groove between

m.extensor digitorum communis and m.extensor carpi ulnaris

Elbow, between the tendon of m.biceps brachii and m.brachioradialis.

Upper arm, in the radial groove

Axilla

Supracalaicular region.

Note: It may be necessary to use needle stimulation electrodes in the forearm and elbow. At these

points the nerve is located below muscles and may be difficult to stimulate. Calipers should be used

to measure the distance in the segment from the elbow to the forearm.

{HYPERLINK \l "MCSradialis"}N. MUSCULOCUTANEUS

Position of limb: Patient supine, sitting or reclining.


Position of recording electrode: Over anterior side of the middle of the long head of m.biceps brachii.

Position of reference electrode: Over the lateral epicondylus.


Stimulation sites:

Axilla, just above the tendon of m.latissimus dorsi


Measurement of distance: For accurate distance measurement it is advisable to use calipers.

{HYPERLINK \l "MCSmusculocut"}N. AXILLARIS

Position of limb: Patient supine, sitting or reclining. Elbow extended and forearm supinated.


Position of recording electrode: In the middle of the lateral side of m. deltoideus.

Position of reference electrode: In the lower third of the upper arm.


Stimulation sites: Supraclavicular region.

{HYPERLINK \l "MCSaxiallaris"}

N. SUPRASCAPULARIS

Position of patient and limb: Patient prone, arm along the side of the trunk.

Type of recording electrodes: Needle or surface electrodes.

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Position of recording electrode: M.infraspintus

Type of stimulating electrodes: Surface electrodes on a fixed bar or near nerve needle electrodes

Stimulation sites: Supraclavicular region

{HYPERLINK \l "MCSuprascap"}

N. THORACICUS LONGUS

Position of limb: Patient prone, sitting or reclining. Arm abducted 90 degrees.


Position of recording electrode: Over m.serratus anterior in the midaxillary line over the sixth or

seventh rib.

Position of reference electrode: Over the sternum.



N. THORACODORSALIS

Position of limb: Patient prone, sitting or reclining.


Position of recording electrode: Over m. latissimus dorsi in the posterior midaxilary line.

Position of reference electrode: Over the eight or nineth rib in the midaxillary line.



N. DORSALIS SCAPULAE

Position of limb: Patient prone, sitting or reclining.

Type of recording electrodes: Needle or surface plate electrodes.

Position of recording electrode: Over m. rhomboideus medial to the scapula at the level of spina

scalulae.

Position of reference electrode: In the midline over the eight or nineth spinous process..


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N. PHRENICUS

Position of patient: Patient supine, sitting or reclining.


Position of recording electrode: At the level of the xiphoid process in the midaxillary line.

Position of reference electrode: Over the anterior superior iliac spine.


Stimulation site: The phrenic nerve is best stimulated percutaneously above the sternum close to the

insertion of the sternocleidomastoideus muscle. If this is not possible it may be stimulated around the

posterior border of m.sternocleidomastoideus, at the upper level of the thyroid cartilage.

{HYPERLINK \l "MCSPhrenicus"}

N. ACCESSORIUS (to m.trapezius)

Position of patient: Patient supine, sitting or reclining. Head turned 45 degrees to the side

contralateral of the measurement.


Position of recording electrode: Over the upper part of m.trapezius, at the junction of the middle and

lateral third of the upper border of the muscle.

Position of reference electrode: Over the acromio-clavivular joint.


Stimulation sites:

At the base of the scull immediately in front of the insertion of m.sternocleidomastoideus.

Posterior triangle of the neck, behind m. sternocleidomastoideus.

{HYPERLINK \l "MCSAccesorius"}N. ACCESSORIUS (to m.sternocleidomastoideus)

Position of patient: Patient supine, sitting or reclining. Head turned 45 degrees to the side

contralateral of the measurement.


Position of recording electrode: Over the midportion of m.sternocleidomastoideus.

Position of reference electrode: Over the sternum.

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Stimulation sites: At the base of the scull immediately in front of the insertion of m.sternocleidomas-

toideus.

Note: This technique is useful in the evaluation of the effect of botulinus toxin in patients that are

suspected of beeing refractory to the toxin.

N. FACIALIS

Position of patient: Supine, sitting or reclining.


Position of recording electrode: Depends on which branch of the facial nerve is studied.

R. temporalis: m.frontalis, 20 mm above the middle of the of the upper border of the orbit

Bischoff: R.zygomaticus: m.orbicularis oculi, below the the lateral third of the eye.

R. zygomaticus: m.nasalis, lateral to the midportion of the nose.

R. buccalis: m.orbicularis oris, on the lateral side of the lip.

R. buccalis: m.mentalis, 20 mm below the lower lip and 20 mm lateral to the midline.

R. mandibularis m.depressor anguli oris, below the lateral side of the lower lip 20 mm above the

margin of the mandible.

R. cervicalis: m.platysma, 3-5 cm in front of the mid-portion of m.sternocleidomastoideus

Position of reference electrode: On the contralateral side in the homologous area.


Stimulation sites: Immediately below and anterior to the pinna of the ear. The individual branches

may be stimulated more distally if necessary.

Anomalies: The branching of the facial nerve is highly variable.

{HYPERLINK \l "MCSFacialis"}N. HYPOGLOSSUS

Position of patient: Supine, sitting or reclining.


Position of recording electrode: Below the chin, overlying m.genioglossus.

Position of reference electrode: Over the same muscle on the contralateral side.


Stimulation sites: The medial to the posterior angle of the mandible.

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N. PERONEUS PROFUNDUS

Position of limb: Patient supine, sitting or reclining.The ankle joint in a relaxed, neutral position.


Position of recording electrode: In the middle of m.extensor digitorum brevis.

Position of reference electrode: At the fifth metatarsophalangeal joint.


Stimulation sites:

Ankle, 80 mm proximal to the recording electrode, lateral to the tendon of m.tibialis anterior.

Below knee, 20-50 mm distal to the proximal part of caput fibulae.

Above knee, 50-90 mm above caput fibulae, medial to the tendon of m.biceps femoris.

Anomalies: m.extensor digitorum brevis is innervated by n.peroneus profundus alone in most

subjects. In some subjects there may be an acessory branch from n.peroneus superficialis to

m.extensor digitorum brevis.

Note: The distance in the segment across the knee should be at least 100 mm.

{HYPERLINK \l "MCSPerprof"}

N. PERONEUS SUPERFICIALIS

Position of patient and limb: Patient supine, sitting or reclining. Leg extended.


Position of recording electrode: Over the belly of m.peroneus longus. The point is over the lateral side

of the leg at the juction of the upper and middle third of the fibula.

Position of reference electrode: Lateral malleolus.


Stimulation sites:

Below knee, 20-50 mm distal to the proximal part of caput fibulae.

Above knee, 50-90 mm above caput fibulae, medial to the tendon of m.biceps femoris

Note: The distance of the segment across the knee should be at least 100 m.

N. PUDENDUS

Position of patient and limb: Patient supine, preferably on a gynecological examination table.

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Type of recording and stimulating electrodes: Special electrode that is mounted over a glowe on the

forefinger. At the tip there is pair of stimulating electrodes and at the base a pair of recording

electrodes (St Mark´s pudendal electrode; Comercially available from Medtronic, type 9013L0402 or

9013L0401)

Position of recording electrodes: Sphincter ani externus, additional electrodes may be placed in the

urethral sphincter.

Position of reference electrode: Sphincter ani externus.

Stimulation site: Laterally over the ischial tuberosity.

Note: Only DLAT and AMPL are measured.

N. TIBIALIS

Position of patient and limb: Patient prone or reclining. Legs extended.


Position of recording electrode: The site of the recording electrode depends on the distal branch that

is under study.

N.plantaris lateralis: over middle of the m.abductor digiti minimi, on the lateral side of the foot.

N.plantaris medialis: over the middle of m.abductor hallucis, this is 10 mm below the posterior part of

the navicular bone.

Position of reference electrode:

N.plantaris lateralis: Over the proximal phalanx of digit V.

N.plantaris medialis: Over the proximal phalanx of digit 1.


Stimulation sites:

Below medial malleolus (around 50 mm below the middle of the malleolus).

Above medial malleolus (around 50 mm above the middle of the malleolus).

Knee, in the fossa poplitea.

{HYPERLINK \l "MCSTibialis"}N. TIBIALIS, H-reflex

Position of patient and limb: Patient prone or reclining. Legs extended.


Position of recording electrode: Over m.soleus halfway between the knee and ankle

Position of reference electrode: Over the Achilles tendon

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Stimulation site: Knee, in the fossa poplitea.

{HYPERLINK \l "Hreflextib"}N. FEMORALIS

Position of patient and limb: Patient supine, sitting or reclining. Hip and knee extended.

Type of recording electrodes: Surface electrodes.

Position of recording electrode:

over m.vastus medialis, on the anterior-medial aspect of the thigh at the junction of the middle and

lover third of the thigh.

over m.vastus lateralis, on the anterior-lateral aspect of the thigh at the junction of the middle and

lover third of the thigh.

over m.rectus femoris, on the anterior aspect, midpoint between the anterior superior iliac spine and

the upper edge of the patella.

Position of reference electrode: Below the medial epicondylus of the knee.


Stimulation site: Surface or needle electrode below the inguinal ligament.

Note: Conduction velocity cannot be calculated, only the conduction time from the inguinal ligament to

muscle is measured. The amplitude and area of the response are also measured.

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MCS Median nerve

MCS n interosseus anterior

MCS n Ulnaris

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MCS n Radialis

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MCS n Musculocutaneus

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MCS n Axillaris

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MCS n Suprascapularis

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MCS n Phrenicus

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MCS n Accesorius

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MCS n Facialis

MCS n Peroneus profundus

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MCS n Tibialis

H-reflex, n Tibialis

motor nerve conduction studies - clinical … · motor nerve conduction studies department of...

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