C6 nerve root !

The C6 nerve root leaves the spine at C5-C6, the second most often pinched neck root; it gives feeling to the thumb side of the forearm and hand.

Official name: C6

See in 3D →

Opens in the Durgical app, no sign-up needed.

What it is

The C6 nerve root, leaving the spine at C5-C6; after C7, the most commonly pinched neck root.

What it does

Supplies the biceps and wrist extensors, the biceps and brachioradialis reflexes, and feeling in the thumb side of the forearm and hand.

Key facts

Roots: C6 dorsal and ventral roots; exits the C5–C6 intervertebral foramen; compressed by a C5–C6 disc herniation
Moves: Biceps, brachialis, brachioradialis, wrist extensors (extensor carpi radialis); biceps and brachioradialis reflexes (C5–C6)
Feeling from: Lateral forearm, thumb and index finger (varies)

Relations

Course: Leaves the C5–C6 foramen behind the vertebral artery and joins C5 to form the upper trunk of the brachial plexus; it also sends fibres to the long thoracic nerve
In front: The C5–C6 disc and uncovertebral joint
Behind: The C5–C6 facet joint

How to find it

It cannot be felt. It leaves through the C5–C6 foramen and lies in the gutter of the C6 transverse process, whose large anterior (carotid) tubercle can be felt deep at the level of the cricoid cartilage; on ultrasound that tubercle identifies the C6 level.

Examination

Resisted wrist extension (extensor carpi radialis longus and brevis), the ISNCSCI C6 key muscle
Brachioradialis reflex: tapping the radial side of the forearm near the wrist; reduced in C6 radiculopathy
Spurling test reproducing pain into the thumb and index finger
Pinprick on the back of the thumb's proximal phalanx (C6 key point)

On imaging

Leaves through the C5–C6 foramen; axial MRI at that level shows the disc or spur pressing on it. On ultrasound the C6 transverse process has a large anterior tubercle (carotid tubercle) and a smaller posterior one, with the root lying between them; this shape names the level. On MRI a high-signal cord at C5–C6 with an inverted brachioradialis reflex points to myelopathy.

Common problems

Cervical radiculopathy: a disc or bone spur pinches a root, causing pain, numbness or weakness down the arm in that root's pattern.

How it is diagnosed

Exam of strength, reflexes and feeling in the arm (each root has its own pattern); MRI; sometimes nerve tests (EMG).

Treatment

Most improve with time, physical therapy, medicine and sometimes an injection.
Lasting pain or weakness: surgery to free the root, such as ACDF or a foraminotomy.

Clinical notes

C6 vs carpal tunnel syndrome: both numb the thumb and index finger, but C6 brings neck and arm pain, a reduced biceps or brachioradialis reflex and weak elbow flexion or wrist extension; carpal tunnel spares the reflexes and weakens thumb abduction
Both can coexist (double crush); nerve conduction studies show slowing at the wrist in carpal tunnel and are normal in a pure root lesion
In tetraplegia at C6, keeping wrist extension allows a tenodesis grip: extending the wrist passively closes the fingers for useful hand function

Test yourself

Think of the answer, then tap the question to see it.

Which disc herniation compresses the C6 nerve root, and where does the pain spread?

A C5–C6 disc herniation (or foraminal spurs); pain spreads down the outer arm to the thumb and index finger.

What are the ISNCSCI key muscle and key sensory point for the C6 nerve root?

Key muscle: wrist extensors (extensor carpi radialis). Key sensory point: back of the thumb over the proximal phalanx.

Which reflexes are reduced in a C6 radiculopathy?

The biceps and brachioradialis reflexes (C5–C6).

How is a C6 radiculopathy told apart from carpal tunnel syndrome?

C6 adds neck and arm pain, a reduced biceps or brachioradialis reflex and weak elbow flexion or wrist extension; carpal tunnel spares reflexes and weakens thumb abduction.

Add to my cards (4)

Educational information, not medical advice. For any symptom, see a health professional.

Its names

Official Latin (TA2): radix nervi spinalis C6 TA2 6363
Official Spanish (DeCS): Raíz C6 DeCS D013126
English (TA2): C6
Also called: spinal nerves C1-C8

Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Head and Neck: Cervical Nerves; Anatomy, Skin, Dermatomes.

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.

C6 nerve root highlighted on the Durgical 3D model