Definition

Cervical radiculopathy is dysfunction of a cervical nerve root resulting in pain in the neck and arm with associated sensory, motor, and reflex abnormalities. Involvement of the ventral root of the spinal nerve results in motor weakness, and involvement of the dorsal root of the spinal nerve results in sensory deficits. Involvement of either root may result in reflex abnormality because the reflex arc comprises both (pertinent to C5, C6, and C7). In most cases, both the ventral and dorsal roots are affected, resulting in motor and sensory cervical radiculopathy.

Cervical radicular pain refers to neck pain radiating to the arm in a specific nerve root pattern, but it is not necessarily associated with loss of sensation, motor deficit, or reflex abnormality. A patient could experience radicular neck pain without abnormal physical examination findings that are characteristic of radiculopathy.

Cervical spine anatomy is complex (Fig. 5.1). There are seven cervical vertebrae (C1-C7). The C1 vertebra is ring shaped, and its lateral masses articulate with the occipital condyle of the skull. The vertebral body of C2 is marked by the cephalad extension of the dens, which is secured in place by the transverse ligament. There are six intervertebral discs (C2-C7) located anteriorly in between vertebral bodies of adjacent vertebrae. C2-C7 vertebrae articulate posterolaterally through facet joints, which are situated in the coronal plane with inferior angulations. C3-C7 vertebrae also have a unique articulation through the uncovertebral joint. There are eight pairs of cervical nerve roots. The names of the cervical nerves correspond to the vertebral body below the nerve, except C8. The C8 roots exit at the C7-T1 intervertebral foramen. The foramina are largest in the upper cervical spine and gradually narrow distally, with the C7-T1 foramen being the narrowest [1]. Cervical nerve roots exit through the inferior portion of the cervical intervertebral foramina [1]. The C1-C3 spinal nerves have dorsal innervations including suboccipital (C1), greater occipital (C2), and third occipital nerves (C3) [2]. The C1-C4 ventral primary rami form the cervical plexus, and the C5-C8 ventral primary rami contribute to the brachial plexus innervating the arm [3]. Each cervical intervertebral foramen is bordered posterolaterally by the zygapophyseal joint (facets), anteromedially by the uncovertebral joint, and inferiorly and superiorly by the pedicles of the adjacent vertebrae. Intervertebral discs are located anteriorly, and they separate vertebral bodies to lend height to the intervertebral foramina.

The most common radiculopathy is C7, followed by C6, C8, and C5 in descending order of incidence [4]. The most common reasons for cervical radiculopathy are posterolateral herniated disc (Fig. 5.2); narrowing of the neuroforamina due to facet spondylosis; hypertrophied uncinate process with neuroforaminal encroachment; and spondylolisthesis, with or without instability, narrowing adjacent neuroforamina. Less common causes include facet synovial cyst with encroachment of nerve root, extradural mass, spinal tumors, and abscess. Other medical conditions that resemble cervical radicular symptoms should be carefully ruled out as part of medical evaluation of neck and arm pain (Table 5.1). These include musculoskeletal, neurologic, and rheumatologic disorders.

Symptoms

The most common symptom of cervical radiculopathy is neck pain with associated unilateral arm pain in a specific nerve root pattern. Sensory complaints of numbness, tingling, burning, or electrical sensation follow a dermatomal pattern, and weakness follows the same anatomic-level myotomal pattern. Of the subjective complaints, the distribution of hand paresthesias appears to have the greatest localizing value [5]. Literature supports that suprascapular (C5-C6), interscapular (C7), and scapular (C8) pain suggests radiculopathy [6]. Symptoms can be aggravated by motion of the head toward the painful side, free hanging of the arm, lifting of heavier items, coughing, sneezing, and Valsalva maneuver. Pulling, pushing, and lifting of items are often not tolerated in the acute phase. Pain may improve when the head is tilted away from the painful side or if the affected arm is abducted over the head. Clumsiness, fine motor deficits, and mild grip weakness may precede gross weakness. Clinicians should routinely inquire about symptoms of myelopathy. Myelopathy symptoms are bilateral hand numbness or paresthesias, altered dexterity, poor balance, falls, and bowel or bladder dysfunction. These symptoms are not features of a discrete radiculopathy and should alert the clinician to rule out spinal cord compression.

Physical Examination

A complete musculoskeletal and neurologic examination is indicated in the evaluation of cervical radiculopathy. Special attention is needed to differentiate between objective findings compatible with radiculopathy and myelopathy signs. Physical examination needs to be expanded if other system involvement is suspected.

Visual Observation

Simple observation is a first step to proper diagnosis and treatment. A clinician’s eyes should be trained to notice poor posture, body mechanics, spinal deformity, muscle atrophy, asymmetric gait, use of assistive devices, skin abnormalities, and nonverbal behaviors.

Gait Evaluation

Examination of gait is an important step in differentiating radicular neck pain from myelopathy. Gait should be normal in cervical radiculopathy and could be abnormal in cervical myelopathic patients.

Palpation

In patients with radiculopathy, ipsilateral tenderness and muscle spasm are common. The clinician should examine muscles for taut bands or tender points.

Range of Motion

Range of motion (ROM) of the cervical spine in all planes should be examined and deficits should be documented. Clinicians should carefully reevaluate ROM of the cervical spine to monitor progress in treatment. The normal cervical ROM is as follows: extension, 55 degrees; flexion, 45 degrees; lateral bending, 40 degrees; rotation, 75 degrees [7]. Among activities of daily living, backing up a car requires the most available range. Personal hygiene, such as hand washing, shaving, and applying makeup, necessitates a significantly greater cervical ROM relative to mobility activities of daily living, including walking and negotiating stairs [7].

Sensory Testing

Radiculopathy results in dermatomal sensory abnormality in the neck, shoulder girdle, and ipsilateral arm. On the basis of the specific dermatomal deficits, a clinician can localize the anatomic level of nerve root impingement. Light touch, pinprick, two-point discrimination, proprioception, and vibration sense should be tested in both the symptomatic and symptom-free arm. There is a degree of overlap between dermatomal innervations of the arm. To date, the International Standards for Neurological Classification of Spinal Cord Injury is the most standardized sensory testing guideline [8]. For consistent examination, the use of these guidelines is recommended to examine sensory function in the upper limb (Fig. 5.3).

Deep Tendon Reflexes

The most frequently tested reflexes in the upper limb are the biceps brachii (innervation C5/6, C5 primary), the brachioradialis (C5/6, C6 primary), and the triceps (C7 primary). Reflexes are tested bilaterally and compared. Hyporeflexia (diminished) or areflexia (complete absence) indicates involvement of the lower motor neuron, including the specific nerve root tested. Hyperreflexia (increased or brisk reflex) is an indication of central nervous system involvement. The response levels of deep tendon reflexes are graded 0 to 4 +, with 2 + being normal (Table 5.2 and Fig. 5.4).

Motor Testing