Cervical · Upper-extremity pattern aid

Cervical disc level → exiting root.

In the cervical spine, disc-level naming maps differently than lumbar levels: a C5–C6 disc lesion most classically affects the C6 root, a C6–C7 lesion affects C7, and C7–T1 affects C8.

Select cervical disc level

Cervical naming rule

Cervical roots C1–C7 exit above their corresponding vertebrae, while C8 exits between C7 and T1. Clinically, subaxial disc lesions are usually described by the lower exiting root at that disc level.

Example A C6–C7 disc lesion most classically causes C7 radiculopathy.

Selected cervical level

C6–C7

Affected root C7 exiting cervical root

Dermatome (sensory)

Myotome (motor)

Reflex

Bedside clue

Dermatomal map

Cervical upper-extremity zones

C7 highlighted
Disc levelClassic rootDermatome MotorReflexCommon mimic / caution

Cervical clinical warning

  • C7 is often reported as the most frequently involved cervical nerve root, while C2–C4 radiculopathy is uncommon [Kang et al.].
  • Classic patterns are imperfect: McAnany et al. found standard textbook pain/numbness patterns in only 54% of 239 single-level surgical cases, with nonstandard patterns differing by an average of 1.68 dermatomal levels [McAnany et al.].
  • Screen for myelopathy when symptoms include hand clumsiness, gait imbalance, hyperreflexia, Babinski, clonus, Hoffmann sign, or bowel/bladder change; signs or symptoms of myelopathy warrant urgent referral [McCartney et al.].

Cervical root patterns synthesize Kang et al., McCartney et al., and the Merck Manual.

Patient view · Dermatome reference

Human dermatome map

Full-body anterior and posterior human dermatome map

Full-body anterior/posterior dermatome reference. Use this enlarged view for patient education and correlate with the selected nerve root findings.

Axial view · Disc morphology

Axial disc morphology

Enlarged axial view of paracentral disc morphology

Axial cut showing the selected herniation morphology and which nerve root it compresses. Educational illustration; not a patient image.