Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

 

Cervical Disc Herniation and Radiculopathy

Introduction

Cervical disc herniation is a common cause of neck pain and upper limb radiculopathy. Herniated disc material compresses a cervical nerve root, leading to characteristic motor, sensory, and reflex abnormalities.

Accurate diagnosis depends on correlating:

• Dermatome
• Myotome
• Reflex changes

---

Common Levels

The most commonly affected cervical disc levels are:

• C6–C7
• C5–C6

These account for the majority of cervical radiculopathy cases.

---

Clinical Presentation

Symptoms

Typical symptoms include:

• Neck pain
• Radiating pain into the ipsilateral upper limb
• Numbness
• Paresthesia
• Weakness

---

Aggravating Factors

Symptoms may worsen with:

• Coughing
• Sneezing
• Neck movement

These maneuvers increase intradiscal and nerve root pressure.

---

Key Clinical Principle

Each cervical nerve root has:

• A motor function
• A sensory distribution
• A corresponding reflex

Accurate localization requires correlation of all three.

---

Nerve Root Level-wise Findings

C4 Nerve Root (C3–C4 Disc)

Sensory Distribution

• Shoulder region

---

Motor Function

• Diaphragm function via the phrenic nerve

---

Clinical Relevance

Severe involvement may affect respiration.

---

C5 Nerve Root (C4–C5 Disc)

Sensory Distribution

• Lateral shoulder

---

Motor Function

• Deltoid
• Elbow flexion

---

Reflex

• Biceps reflex

---

C6 Nerve Root (C5–C6 Disc)

Sensory Distribution

• Thumb
• Index finger

---

Motor Function

• Wrist extension
• Elbow flexion

---

Reflex

• Brachioradialis reflex

---

C7 Nerve Root (C6–C7 Disc)

Sensory Distribution

• Middle finger

---

Motor Function

• Triceps
• Wrist flexion
• Finger extension

---

Reflex

• Triceps reflex

---

C8 Nerve Root (C7–T1 Disc)

Sensory Distribution

• Ring finger
• Little finger
• Medial forearm

---

Motor Function

• Finger flexion
• Grip strength

---

Reflex

• No reliable reflex

---

T1 Nerve Root (T1–T2 Disc)

Sensory Distribution

• Medial arm

---

Motor Function

• Interossei muscles
• Finger abduction and adduction

---

Reflex Summary

---

Clinical Localization Tips

C6 Radiculopathy

Typical findings:

• Thumb and index finger numbness
• Wrist extension weakness

---

C7 Radiculopathy

Most common cervical radiculopathy.

Typical findings:

• Middle finger numbness
• Triceps weakness
• Reduced triceps reflex

---

C8 Radiculopathy

Typical findings:

• Weak grip strength
• Finger flexion weakness

---

C5 Radiculopathy

Typical findings:

• Shoulder weakness
• Deltoid weakness
• Reduced biceps reflex

---

Important Cervical Spine Rule

In the cervical spine:

• A disc herniation usually compresses the lower exiting root

Example:

• C6–C7 disc herniation affects the C7 root

This is called the lower root rule.

---

Red Flag Signs

Important warning signs include:

• Progressive weakness
• Myelopathic features
• Respiratory involvement
• Bilateral neurological symptoms
• Gait disturbance

---

Management Overview

Conservative Treatment

First-line treatment includes:

• NSAIDs
• Physiotherapy
• Activity modification
• Cervical posture correction

Most patients improve without surgery.

---

Indications for Surgery

Surgical treatment may be required for:

• Persistent symptoms beyond 6–12 weeks
• Progressive neurological deficit
• Significant motor weakness
• Cervical myelopathy

---

Key Clinical Pearls

• Most common cervical disc levels: C5–C6 and C6–C7
• Most common radiculopathy: C7
• Middle finger numbness suggests C7 involvement
• Thumb and index finger symptoms suggest C6 involvement
• Biceps reflex corresponds mainly to C5
• Triceps reflex corresponds mainly to C7
• There is no reliable reflex for C8 radiculopathy
• Always correlate dermatome, myotome, and reflex findings for accurate localization