Topics

Topic

design image
Cervical spinal nerve 6 (C6)

The cervical spinal nerve 6 (C6) is one of the key nerves originating from the cervical region of the spinal cord, specifically between the C5 and C6 vertebral bodies. It plays a critical role in the motor and sensory innervation of the upper limb, particularly the forearm and thumb region. C6 is frequently evaluated in clinical and imaging settings due to its association with common neurological and musculoskeletal pathologies.

Synonyms

  • C6 nerve

  • Sixth cervical nerve

  • Cervical nerve 6

  • Sixth cervical spinal nerve

Function

  • Provides motor innervation primarily to the biceps brachii, brachialis, brachioradialis, and extensor carpi radialis longus muscles.

  • Contributes to the brachial plexus, forming part of the upper (lateral) trunk.

  • Responsible for sensory supply to the lateral forearm and the thumb (radial side of the hand).

  • Involved in the biceps reflex (C5-C6 deep tendon reflex).

MRI Appearance

  • T1-weighted images:

    • C6 nerve roots appear as low-to-intermediate signal structures within the neural foramen, surrounded by high-signal epidural fat.

  • T2-weighted images:

    • Normal C6 nerve roots show intermediate signal, easily visualized against high-signal CSF background. Hyperintensity may indicate nerve edema or inflammation.

  • STIR (Short Tau Inversion Recovery):

    • C6 nerve appears as low signal; any high signal suggests nerve pathology (edema, neuritis).

CT Appearance

  • C6 nerve is not well visualized on CT unless enlarged or affected by pathology.

  • CT myelogram can better outline the nerve root, showing its course within the neural foramen.