Arm and Neck Pain - Clinical Tree

Evaluation of the patient with arm and/or neck pain is based on a meticulous history and clinical examination.

A useful approach is to consider the diagnosis in terms of pain-sensitive structures in the neck and upper limbs. These structures may be part of the nervous system or may involve joints, muscles, and tendons. Neurological causes of pain should be considered based on the innervation of the neck and arm; nonneurological causes are based on dysfunction of the other anatomical structures of the arm or neck. Because nerve root irritation generates neck muscle spasm, this type of pain is usually lumped into the “neurological” category. Some essentially nonneurological conditions have neurological complications and are grouped in this chapter as “in-between” disorders.

If the pain can be reproduced by joint movement at any level, the underlying cause is more likely to be rheumatological than neurological.

Clinical Assessment

History

Neurological Causes of Pain: Sites That Can Trigger Pain

Muscle spasm

Posterior cervical muscles in spasm trigger local pain that is aggravated by neck movement, and the diagnosis is supported by the finding of palpable spasm and tenderness. The pain may radiate upward to the occipital region and over the top of the head to the bifrontal area. It is usually described as constant, aching, bursting, or as a tight band or pressure sensation on top of the head. Pain with similar characteristics can be triggered by pathology in the facet joints, cervical vertebrae, and even intervertebral disk pathology. These are often causative in the genesis of neck muscle spasm.

Neck mobility is best assessed by testing flexion and extension, lateral flexion to the right and left, and rotation to the right and left. Normally with flexion, the chin can touch the sternum; in rotation, the chin can approximate the point of the shoulder. Restriction of movement, particularly rotation, usually indicates the presence of cervical spondylosis.

Central pain

Dysfunction affecting the ascending sensory tracts in the spinal cord may generate pain or paresthesias in the arms or down the trunk and lower limbs. An electric shock–like sensation provoked by neck flexion that spreads to the arms, down the spine, and even into the legs is thought to originate in the posterior columns of the cervical spinal cord (Lhermitte sign). Although this symptom is frequent in patients with multiple sclerosis (MS), it is nonspecific and simply indicates a pathological process in the cervical cord. Sharp superficial burning pain or itching points to dysfunction in the spinothalamic system, whereas deep aching boring pain with paresthesias of tightness, squeezing, or a feeling of swelling suggests dysfunction in the posterior column proprioceptive system. Sensory symptoms indicate which tract is dysfunctional, but they are poor segmental localizers.

Nerve root pain

If the pathology involves a nerve root, it is referred to the upper limb in a dermatomal distribution. Brachialgia (arm pain) aggravated by neck movement, coughing, or sneezing suggests radiculopathy; when these trigger features are present, one can be fairly certain that the pain is radicular in origin. Nerve root pain is typically lancinating in character, but it can present as a dull ache in the arm.

Repetitive sudden shooting pains radiating from the occipital region to the temporal areas or vertex suggest the diagnosis of occipital neuralgia. There may be local tenderness over the greater or lesser occipital nerve, and a local injection of corticosteroid plus local anesthetic is both diagnostic and therapeutic. Failure to respond suggests that the area of the craniovertebral junction should be imaged.

Ulnar nerve pain

Ulnar nerve entrapment triggers numbness or pain radiating down the medial aspect of the arm to the little and ring fingers. Symptoms are often worse at night when the patient sleeps with a flexed elbow, and they may interrupt sleep. Ulnar paresthesias are also triggered by pressure on the nerve when the patient is resting the elbow on the arm of a chair or desk. Tapping on the nerve in the ulnar groove at the elbow may evoke a tingly electrical sensation in the little and ring fingers (Tinel sign).

Median nerve pain

Median nerve entrapment in the carpal tunnel classically awakens the patient from sleep with numbness and tingling in the thumb, index, and middle fingers, which is relieved by “shaking out” the hand. Pain generated in the median nerve can be sharp and lancinating and radiates to the thumb, index, and middle fingers. Although entrapment in the carpal tunnel is common, occasionally the site of entrapment is close to the elbow as the nerve passes under the pronator muscle.

Plexus pain

Infiltrative or inflammatory lesions of the brachial plexus produce severe brachialgia radiating from the shoulder region and spreading down the arm. Radiation to the ulnar two fingers suggests that the origin is in the lower brachial plexus, and radiation to the upper arm, forearm, and thumb suggests an upper plexopathy. The thoracic outlet syndrome is an overdiagnosed condition but certainly exists. Patients with thoracic outlet syndrome complain of brachialgia and numbness or tingling in the upper limb or hand when they are working with objects above the head; thoracic outlet maneuvers are designed to test for compromise of the neurovascular structures passing through the thoracic outlet. The arm is extended at the elbow, abducted at the shoulder, and then rotated posteriorly. The examiner palpates the radial pulse while listening with a stethoscope over the brachial plexus in the supraclavicular fossa. The patient takes a deep inspiration and turns his or her head to one or the other side. Many normal individuals lose their radial pulse when doing this, but a bruit heard over the plexus does suggest, at the least, vascular entrapment (Adson test). The patient then exercises hands held above the head and extended elbows—numbness, pain, or paresthesias, often with pallor of the hand, support the diagnosis of thoracic outlet syndrome (Roos test) ( Fig. 32.1 ).

Nonneurological Causes of Neck Pain and Brachialgia

Muscle pain is deep, aching, and boring. In the cervical region, it is localized to the shoulders and sometimes radiates down the arm. If the patient with myalgia is over 50 years of age, a markedly elevated sedimentation rate would suggest the diagnosis of polymyalgia rheumatica. Patients with fibromyalgia may have pain in the neck, shoulders, and arms, with trigger spots or nodules that are exquisitely tender even to light pressure.

If pain is triggered or aggravated by joint movement of the upper limb, arthritis or tendonitis is the likely cause. Pain on shoulder abduction is usually related to Tendonitis, rotator cuff pathology, or pericapsulitis. The tendons anteriorly and at the lateral point of the shoulder may be tender to pressure. More diffuse tenderness anterior to the shoulder joint suggests bursitis. Tenderness over the medial or lateral epicondyle at the elbow indicates local inflammatory epicondylitis, and pain on active or passive wrist or finger joint movement suggests tendonitis or arthritis of the fingers. The pain of epicondylitis may radiate down the forearm in a pseudoneuralgic fashion, but precipitation by wrist extension or grip indicates a rheumatological cause.

Examination

The physical examination is designed to define the neurological signs which localize the pathology to spinal cord, nerve roots, or peripheral nerves. Evaluation for nonneurological pathology is also necessary because rheumatological problems often complicate a primarily neurological problem. A detailed knowledge of motor and sensory neuroanatomy is required for accurate localization.

Motor Signs—Atrophy and Weakness

The examination begins with inspection. Particular attention is paid to atrophy of muscles of the shoulders and arms and the small muscles of the hands. Fasciculations are associated with anterior horn cell disease, but they may be part of the neurology of cervical spondylosis and radiculopathy. Significant sensory signs would argue against anterior horn cell degeneration.

Muscles in the various myotomes are tested individually. When there is unilateral weakness, the contralateral side can act as a control, but some standard measure of strength is necessary for accurate evaluation when bilateral weakness is present. If one can overcome the action of a muscle by resisting or opposing its action close to the joint it moves, using an equivalent equipotent muscle of the examiner (fingers test fingers, whole arm tests biceps), then that muscle is by definition, weak. The degree of weakness can be graded, and the five-point (Medical Research Council [MRC]) grading scale is often used. Grade 5 represents normal strength. Grade 4 represents “weakness” somewhere between normal strength and the ability to move the limb only against gravity (grade 3). Grade 4 covers such a wide range of weakness that it is usually expanded. One simple expansion is into mild, moderate, or severe. When the muscle can move the joint only with the effect of gravity eliminated, it is graded at 2, and grade 1 is just a flicker of movement.

Hypertonia, weakness, sensory loss, increased tendon reflexes, and/or extensor plantar reflexes indicate cord dysfunction; when combined with radicular signs in the upper limbs, a spinal cord lesion in the neck at the level of the root signs is indicated. The distribution or pattern of weakness is all important in localizing the problem to root, plexus, peripheral nerve, muscle, or even upper motor neuron (central weakness). It is useful to use a simplified schema of radicular anatomical localization when one is evaluating nerve root weakness because overlap of segmental innervation of muscles can complicate the analysis ( Table 32.1 ) If the pattern of weakness does not conform to a clearly defined anatomical distribution of cervical roots or a single peripheral nerve, a plexopathy is likely. Upper plexus lesions cause mainly shoulder abduction weakness, and lower plexus lesions cause weakness of the small muscles of the hand.

TABLE 32.1

Segmental Innervation Scheme for Anatomical Localization of Nerve Root Lesions

Segment Level	Muscle(s)	Action
C4	Supraspinatus	First 10 degrees of shoulder abduction
C5	Deltoid	Shoulder abduction
	Biceps/brachialis/brachioradialis	Elbow flexion
C6	Extensor carpi radialis longus	Radial wrist extension
C7	Triceps	Elbow extension
C7	Extensor digitorum	Finger extension
C8	Flexor digitorum	Finger flexion
T1	Interossei	Finger abduction and adduction
	Abductor digiti minimi	Abduction of the little finger

Sensory Signs

Skin sensation is tested in a standardized manner, starting with pinprick appreciation at the back of the head (C2), followed by sequentially testing sensation in the cervical dermatomes, passing down the shoulder, over the deltoid, down the lateral aspect of the arm to the lateral fingers, and then proceeding to the medial fingers and up the medial aspect of the arm ( Fig. 32.2 ). The procedure is repeated with a wisp of cotton to test light touch sensation; test tubes filled with cold and warm water are used to test temperature sensation. Position sense in the distal phalanx of a finger is tested by immobilizing the proximal joint and supporting the distal phalanx on its medial and lateral sides and then moving it up or down in small increments. The patient, with eyes closed, reports the sensation of movement and its direction. Loss of position sense in the fingers usually indicates a very high cervical cord lesion.

Fig. 32.2, Diagram of the Dermatomes in the Upper Limbs.

Tendon Reflexes

An absent tendon reflex helps to localize segmental nerve root levels, but in cervical spondylosis, which is by far the most common underlying pathology, the reflexes are often preserved or even increased despite radiculopathy because of an associated myelopathy. An absent or decreased biceps reflex localizes the root level to C5, and an absent triceps reflex localizes the level to C6 or C7. An absent biceps reflex but with spread so that triceps or finger flexors contract is called an inverted biceps jerk and is strong evidence for C5 radiculopathy.

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