Examination of Nerves of Upper Limb

Examination of Nerves Of Upper Limb

Learning Objectives

At the end of the lecture, the student should be able to:

q  Know steps of neurological examination of the upper limbs.

q  Define the terms Tone, Bulk & Power.

q  What are deep tendon reflexes?

q  Describe Light touch & Pin Prick, Vibration & Proprioception.

q  Describe the Major Nerves of Upper Limb.

Examination of Nerves Of Upper Limb

Neurological Examination of Upper Limbs

Done in Four Steps:

•  Tone

•  Bulk

•  Power.

•  Sensations.

Tone

•  Muscle tone is defined as the resistance to passive stretching.

•  Start at the shoulder, feeling how easy the joint is to move passively. Then move down to the elbow, wrist and hand joints again assessing each limb’s tone in turn.

Bulk & Size

•  Measure the circumference of the patient’s forearm and arm, right and left, where the circumference is greatest and record the measurements.

•  Look and feel the small muscles of the patient’s hands when looking at the thenar and hypothenar eminences. Always adduct all fingers and the thumb.

•  Look at the dorsum of the hand, noting the prominence of the extensor tendons.

Muscle Power

•  Assess the power of each of the muscle groups.

Abduction of Arm (C5)

•  Supraspinatus –Supraspinatus Nerve: Stand behind the patient. He should let his arms hang by his sides. Hold his elbow into the side of his trunk while he attempts to abduct the arm.

•  Deltoid-Axillary Nerve: Resist abduction after the arm has been abducted 45 degrees and more away from the trunk.

Arm Adduction (C7)

•  Pectoralis Major- Pectoral Nerves

•  Latissimus Dorsi-Thoracodorsal Nerve

Have the patient flex at the elbow while the arm is held out from the body at forty-five degrees. Then provide resistance as they try to further adduct at the shoulder. Test each shoulder separately.

Fixation of Scapula

•  Trapezius Muscle-Spinal Accessory Nerve

Pulls scapula up and medial like in shoulder shrug.

•  Rhomboids-Dorsal Scapular Nerve

Pull scapula upward and medially like in shruging the shoulder.

•  Serratus Anterior-Long Thoracic Nerve

Pulls scapula away from midline and forward.

Forearm Flexion (C5-6)

•  Brachialis-Musculocutaneous

•  Biceps Brachii-Musculocutaneous

Have the patient bend their elbow to ninety degrees while keeping their palm directed upwards. Then direct them to flex their forearm while you provide resistance.

Forearm Extension (C7)

•  Triceps Brachii-Radial nerve

Have the patient extend their elbow against resistance while the arm is held out (abducted at the shoulder) from the body at ninety degrees.

Wrist Flexion (C7,8 T1)

•  Flexor Capii Radialis-Median Nerve

•  Flexor Carpii Ulnaris-Ulnar Nerve

Let the patient flex his wrist against your resistance.

Wrist Extension (C7,8)

•  Extensor Carpi Radialis (Longus and Brevis)-Radial Nerve

•  Extensor Carpi Ulnaris-Posterior Interosseous Nerve

Let the patient to try to extend his wrist against your resistance.

Finger Flexion (C7,8T1)

•  Flexor Digitorum Superficialis-Median Nerve

•  Flexor Digitorum Profudus-Ulnar & Anterior Interosseous branch of Median.

Ask the patient to grip and squeeze your two fingers. If the grip is normal, you will not be able to pull your fingers out.

Finger Extension (C7)

•  Extensor Digitorum-Posterior Interosseous branch of Radial.

Ask the patient to keep his hand and wrist stiff and prone. Use the edge of your left hand as a fulcrum in the middle of the patient’s palm. Attempt to flex the patient’s fingers with your right hand.

Thumb Abduction (C7,8 T1)

•  Abductor Pollicis Longus-Radial Nerve

•  Abductor Pollicis Brevis-Median Nerve

Put the dorsum of the patient’s hand on a flat surface. As him to raise the thumb vertically. The surface of the pad of the thumb is at right angles to the surface of the palm of the hand. Apply resistance in opposite direction.

Thumb Opposition (T1)

•  Opponens Pollicis: Median Nerve

Ask the patient to make pincer grip by pushing tips of thumb and small finger. You have to pull open it with force.

Finger Abduction (C8,T1)

•  Dorsal Interossei & Abductor Digiti Minimi-Ulnar Nerve

Ask the patient to spread their fingers apart against resistance.

Finger Adduction (C8,T1)

•  Palmar interossei-Ulnar Nerve

To test for finger adduction, ask the patient to extend his fingers and hold a piece of paper between two of fingers. Then you pull it out.

Deep Tendon Reflexes

There are three reflexes in the upper limb -

•  Biceps

•  Triceps

•  Supinator

It is vital to get your patient to relax as much as possible.

Biceps Jerk

•  Support the patient's arm, with it flexed at roughly 60º, placing your thumb over the biceps tendon and hitting your thumb with the tendon hammer.

Triceps Jerk

•  The triceps reflex is elicited by resting the patient's arm across their chest and hitting the triceps tendon just proximal to the elbow.

Supinator Jerk

•  With the arm rested on abdomen, locate the supinator tendon as it crosses the radius, place three fingers on it and hit the fingers. This should give the supinator reflex.

Sensations

Tested in different ways

•  Light touch

•  Pin prick

•  Vibration

•  Joint position or proprioception

Light touch & Pin Prick

•  Lightly touch the patient's sternum with a piece of cotton wool so that they know how it feels.

•  With eyes shut, lightly touch their arm with the cotton wool.

•  The places to touch them should test each of the dermatomes - make sure you know these!

•  Tell the patient to say yes every time the cotton wool is felt as it felt before.

•  Repeat this using a light pin prick.

Vibration

•  Use a sounding tuning fork (128 hz).

•  Place the fork on the patient's sternum to show them how it should feel.

•  Then place it on the bony prominence at the base of their thumb and ask if it feels the same.

•  If it does, there is no need to check any higher.

•  If it feels different move to the radial stylus and then to the olecranon until it feels normal.

Proprioception

•  Hold the distal phalanx of the thumb on either side so that interphalangeal joint can be flexed.

•  Show the patient that when you hold the joint extended, that represents 'Up' whereas when you hold it flexed that represents 'Down'.

•  Ask the patient to close the eyes and, having moved the joint a few times hold it in one position - up or down. Ask which position the joint is in.

Dermatomes

Upper extremity dermatome innervation with the arm supinated on an arm board

Upper extremity dermatome innervation with the arm pronated on an arm board.

Sensory Nerves

Cutaneous nerve distribution of the upper limb

Major Nerves of Upper Limb

Major Nerves

Nerve / Sensory Supply / Motor Supply / Root Value
Radial Nerve / Back of thumb, index, middle, and 1/2 ring finger;
back of forearm / Wrist extension and abduction of thumb in palmer plane / C6, 7, 8
Ulnar Nerve / Palmar and dorsal aspects of pinky and 1/2 of ring finger / Abduction of fingers (intrinsic muscles of hand) / C7, 8, T1
Median Nerve / Palmar aspect of the thumb, index, middle and 1/2 ring finger; palm below these fingers. / Abduction of thumb perpendicular to palm (thenar muscles). / C8, T1