What is the relationship between chronic neck and shoulder pain?

Relationship Between Chronic Neck and Shoulder Pain

Chronic neck and shoulder pain are often interconnected, with pathology in one area frequently causing referred pain and dysfunction in the other due to shared neurological pathways and biomechanical relationships.

Pathophysiological Connections

• Cervical radiculopathy is a common cause of chronic neck pain with an estimated annual incidence of 83 per 100,000 persons, frequently presenting as neck and/or upper limb pain with varying degrees of sensory or motor deficits 1
• Nerve root compression or irritation in the cervical spine can refer pain to the scapular and shoulder regions 2
• Shoulder impingement can present primarily as neck pain, particularly near the superomedial aspect of the scapula, creating a bidirectional relationship 3
• Patients with chronic neck pain demonstrate altered muscle activation patterns in the shoulder complex, including increased onset delays in the anterior and middle deltoid muscles and peak delays in the upper trapezius 4

Diagnostic Considerations

• MRI is the most sensitive imaging modality for soft tissue abnormalities but should not be used alone to diagnose symptomatic cervical radiculopathy due to frequent false-positive and false-negative findings 1
• Radiographs are frequently ordered as first-line imaging for chronic neck and cervical pain, useful for initial assessment of spondylosis, degenerative disc disease, and malalignment 1
• CT is not recommended as a first-line examination for chronic neck pain without red flags or neurological symptoms 1
• Spondylotic changes on imaging are common in patients over 30 years of age and correlate poorly with the presence of neck pain 1
• Diagnostic evaluation should consider both areas even when symptoms present primarily in one location 3

Biomechanical Factors

• Chronic neck pain can alter shoulder complex muscle activation characteristics, potentially predisposing to shoulder dysfunction 4
• Pain-related changes in motor coordination include:
  • Decreased working rhythm and protective reorganization of muscle synergy 5
  • Higher EMG frequency content indicating altered motor unit recruitment 5
  • Greater postural activity and increased arm and trunk movements 5
• In hemiplegic patients, shoulder pain is associated with abnormal joint mechanics, including capsular stiffness and altered resting position of the scapula 1

Neurological Connections

• Functional MRI studies show that chronic neck and shoulder pain patients demonstrate changes in spontaneous brain activities, including:
  • Increased regional homogeneity in the bilateral middle frontal gyrus 6
  • Decreased regional homogeneity in areas related to pain processing and motor control (insula, superior frontal gyrus, middle cingulate gyrus, supplementary motor area) 6
• These central nervous system changes may contribute to the perpetuation of pain between the neck and shoulder regions 6

Common Pathologies Affecting Both Areas

• Fluid accumulation in various shoulder structures can cause pain that may be perceived in both shoulder and neck regions 7
• Rotator cuff pathology can refer pain to the scapular region, particularly during throwing motions 2
• Inflammatory conditions such as bursitis, tendinopathy, and arthritis can affect both neck and shoulder structures 7

Clinical Pitfalls and Considerations

• Patients often present with pain in one area (neck or shoulder) when the primary pathology is in the other area 3
• Chronic neck and shoulder pain is typically multifactorial, involving both mechanical and inflammatory components 7
• The presence of abnormal findings on imaging does not always correlate with the severity of pain 1
• In a study of 1,581 patients between 18 and 97 years of age, 53.9% demonstrated disc degenerative changes, with prevalence increasing with age, but the association with clinical symptoms remains unclear 1

Treatment Implications

• Addressing both neck and shoulder mechanics is often necessary for successful management 3
• For patients with shoulder impingement presenting as neck pain, treatment directed at the shoulder (such as subacromial injections) can provide relief of neck symptoms 3
• Strong recommendations exist against joint radiofrequency ablation, epidural injections, and joint-targeted injections for chronic spine pain 1
• Conservative approaches including proper positioning, maintenance of range of motion, and motor retraining may benefit patients with interconnected neck and shoulder pain 1