C6 Nerve Root

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Level	Root	Pain & Sensory Change	Motor Weakness	Abnormal Reflexes
C4/C5	C5	Deltoid1 Lateral arm1	Deltoid1 Biceps1	Bicep reflex1
C5/C6	C6	Radial forearm to thumb and index finger1	Biceps1 Wrist extensor1	Bicep reflex1 Brachioradialis reflex1
C6/C7	C7	Midradial forearm to index and middle finger1	Wrist Flexor1 Tricep1	Triceps reflex1
C7/T1	C8	Ulnar forearm to ring and little finger1	Hand Intrinsic1 Finger Flexor1	N/a1

Motor Innervation

C6 Nerve Root Skeletal Muscle Innervations
Muscle	Origin	Insertion	Innervation	Action
Anterior scalene	Anterior tubercle of TP of C3-C62 Anterior tubercle of TP of C3-C6 [@gilroyAtlasAnatomy2020]	Scalene tubercle of 1st Rib2 Scalene tubercle of 1st Rib [@gilroyAtlasAnatomy2020]	Anterior Rami2 C4 - C62 Anterior Rami [@gilroyAtlasAnatomy2020] C4 - C6 [@gilroyAtlasAnatomy2020]	Fixed ribs (bil) C/s flexion [@gilroyAtlasAnatomy2020] Cervical lateral stabilization [@finandoTriggerPointTherapy2005] Fixed ribs (unilateral) I/L C/s sidebend (unilateral) [@gilroyAtlasAnatomy2020] Mobile ribs Elevates ribs during forced inspiration [@gilroyAtlasAnatomy2020]
Coracobrachialis	Coracoid process2 [Coracoid process](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#origin) [@gilroyAtlasAnatomy2020]	Humerus (in line with crest of lesser tubercle)2 [Humerus (in line with crest of lesser tubercle)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#insertion) [@gilroyAtlasAnatomy2020]	Musculocutaneous n.2 C5 - C72 [Musculocutaneous n.](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#nerve) [@gilroyAtlasAnatomy2020] [C5](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#nerve) - [C7](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#nerve) [@gilroyAtlasAnatomy2020]	GHJ [Flexion](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#action) [@gilroyAtlasAnatomy2020] [Adduction](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#action) [@gilroyAtlasAnatomy2020] [IR](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Arm Anterior Muscles/coracobrachialis.html#action) [@gilroyAtlasAnatomy2020]
Middle scalene	C1-C2 TP2 Posterior tubercle of TP of C3-C72 C1-C2 TP [@gilroyAtlasAnatomy2020] Posterior tubercle of TP of C3-C7 [@gilroyAtlasAnatomy2020]	1st Rib (posterior to groove for subclavian a.)2 1st Rib (posterior to groove for subclavian a.) [@gilroyAtlasAnatomy2020]	Anterior Rami2 C3 - C82 Anterior Rami [@gilroyAtlasAnatomy2020] C3 - C8 [@gilroyAtlasAnatomy2020]	Fixed ribs (bil) C/s flexion [@gilroyAtlasAnatomy2020] Cervical lateral stabilization [@finandoTriggerPointTherapy2005] Fixed ribs (unilateral) I/L C/s sidebend (unilateral) [@gilroyAtlasAnatomy2020] Mobile ribs Elevates ribs during forced inspiration [@gilroyAtlasAnatomy2020]
Pectoralis major	Clavicle (medial half)2 Sternum2 Costal cartilages 1-62 Rectus sheath (anterior layer)2 [Clavicle (medial half)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020] [Sternum](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020] [Costal cartilages 1-6](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020] [Rectus sheath (anterior layer)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020]	Humerus (crest of greater tubercle)2 [Humerus (crest of greater tubercle)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#insertion) [@gilroyAtlasAnatomy2020]	Lateral pectoral n.2 Medial pectoral n.2 C5 - T12 [Lateral pectoral n.](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) [@gilroyAtlasAnatomy2020] [Medial pectoral n.](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) [@gilroyAtlasAnatomy2020] [C5](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) - [T1](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) [@gilroyAtlasAnatomy2020]	Clavicular & Sternocostal parts [Flexion](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020] [Aids in respiration when shoulder is fixed](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020] Entire muscle [Adduction](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020] [IR](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020]
Posterior scalene	Posterior tubercle of TP of C5-C72 Posterior tubercle of TP of C5-C7 [@gilroyAtlasAnatomy2020]	2nd Rib (outer surface)2 2nd Rib (outer surface) [@gilroyAtlasAnatomy2020]	Anterior Rami2 C6 - C82 Anterior Rami [@gilroyAtlasAnatomy2020] C6 - C8 [@gilroyAtlasAnatomy2020]	Fixed ribs (bil) C/s flexion [@gilroyAtlasAnatomy2020] Cervical lateral stabilization [@finandoTriggerPointTherapy2005] Fixed ribs (unilateral) I/L C/s sidebend (unilateral) [@gilroyAtlasAnatomy2020] Mobile ribs Elevates ribs during forced inspiration [@gilroyAtlasAnatomy2020]
Serratus anterior	1-9 Ribs2 [1-9 Ribs](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#origin) [@gilroyAtlasAnatomy2020]	Superior angle of Scapula (costal and dorsal surfaces)2 Medial border of scapula (costal surface)2 Medial border of scapula (costal surface)2 Inferior angle of Scapula (costal & dorsal surfaces)2 [Superior angle of Scapula (costal and dorsal surfaces)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#insertion) [@gilroyAtlasAnatomy2020] [Medial border of scapula (costal surface)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#insertion) [@gilroyAtlasAnatomy2020] [Medial border of scapula (costal surface)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#insertion) [@gilroyAtlasAnatomy2020] [Inferior angle of Scapula (costal & dorsal surfaces)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#insertion) [@gilroyAtlasAnatomy2020]	Long thoracic n.2 C5 - C72 [Long thoracic n.](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#nerve) [@gilroyAtlasAnatomy2020] [C5](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#nerve) - [C7](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#nerve) [@gilroyAtlasAnatomy2020]	Entire mm. [Protraction](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#action) [@gilroyAtlasAnatomy2020] [Rib elevation (with fixed shoulder)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#action) [@gilroyAtlasAnatomy2020] Inferior part [Rotates scapula laterally forward](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#action) [@gilroyAtlasAnatomy2020] Superior part [Lowers raised arm](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/serratus_anterior_muscle.html#action) [@gilroyAtlasAnatomy2020]
Splenius capitis	Nuchal lig.2 C7-T4 SP2 Nuchal lig. [@gilroyAtlasAnatomy2020] C7-T4 SP [@gilroyAtlasAnatomy2020]	Lateral third of nuchal line2 Mastoid process2 Lateral third of nuchal line [@gilroyAtlasAnatomy2020] Mastoid process [@gilroyAtlasAnatomy2020]	Spinal nn.2 Posterior rami (lateral br.)2 C1 - C62 Spinal nn. [@gilroyAtlasAnatomy2020] Posterior rami (lateral br.) [@gilroyAtlasAnatomy2020] C1 - C6 [@gilroyAtlasAnatomy2020]	Bilateral Head and neck extension [@gilroyAtlasAnatomy2020] Unilateral I/L sidebend [@gilroyAtlasAnatomy2020] I/L rotation [@gilroyAtlasAnatomy2020]
Splenius cervicis	T3-T7 SP2 T3-T7 SP [@gilroyAtlasAnatomy2020]	C1-C4 SP2 C1-C4 SP [@gilroyAtlasAnatomy2020]	Spinal nn.2 Posterior rami (lateral br.)2 C1 - C62 Spinal nn. [@gilroyAtlasAnatomy2020] Posterior rami (lateral br.) [@gilroyAtlasAnatomy2020] C1 - C6 [@gilroyAtlasAnatomy2020]	Bilateral Head and neck extension [@gilroyAtlasAnatomy2020] Unilateral I/L sidebend [@gilroyAtlasAnatomy2020] I/L rotation [@gilroyAtlasAnatomy2020]
Subclavius	1st rib2 [1st rib](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/subclavius_muscle.html#origin) [@gilroyAtlasAnatomy2020]	Clavicle (inferior surface)2 [Clavicle (inferior surface)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/subclavius_muscle.html#insertion) [@gilroyAtlasAnatomy2020]	N. to subclavius2 C5 - C62 [N. to subclavius](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/subclavius_muscle.html#nerve) [@gilroyAtlasAnatomy2020] [C5](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/subclavius_muscle.html#nerve) - [C6](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/subclavius_muscle.html#nerve) [@gilroyAtlasAnatomy2020]	SCJ [Clavicular stabilization](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/subclavius_muscle.html#action) [@gilroyAtlasAnatomy2020]
Supraspinatus	Supraspinous Fossa of scapula2 [Supraspinous Fossa of scapula](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#origin) [@gilroyAtlasAnatomy2020]	Greater tubercle of Humerus2 [Greater tubercle of Humerus](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#insertion) [@gilroyAtlasAnatomy2020]	Suprascapular n. (C4, C5, C6)2 C4 - C62 [Suprascapular n. (C4, C5, C6)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#nerve) [@gilroyAtlasAnatomy2020] [C4](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#nerve) - [C6](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#nerve) [@gilroyAtlasAnatomy2020]	Stabilization2 GHJ ER2 [Stabilization](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#action) [@gilroyAtlasAnatomy2020] GHJ [ER](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#action) [@gilroyAtlasAnatomy2020]

Contribution

C6 along with C5 contribute to the Superior trunk of the brachial plexus.

Lesion

“This nerve root is often compressed by disc herniation at the C5 C6 vertebral level. A monoradiculopathy affecting the C6 nerve root is the second most common level of cervical radiculopathy after lesions of the C7 level [28]. C6 root involvement results in pain in the lateral arm and dorsal forearm. Sensory signs and symptoms occur on the lateral forearm, lateral hand, and the first and second digits. Paresis occurs predominantly in the following muscles: serratus anterior, biceps, pronator teres, flexor carpi radialis, brachioradialis, extensor carpi radialis longus, supinator, and extensor carpi radialis brevis (examination of these muscles is described in Chapter 2 ). The biceps reflex (segments C5 C6) and the brachioradialis reflex (segments C5 C6) may be depressed. An “inverted radial reflex” occurs when the lesion causes compression of the spinal cord at the C5 C6 level. A central disc prolapse or a horizontal bar due to degenerative disc disease is often responsible for this clinical finding. Damage of the corticospinal tract at the level of C5 C6 results in hyperreflexia at lower levels. Therefore, tapping the tendon of the brachioradialis muscle elicits no response by the brachioradialis but a brisk contraction of the finger flexors innervated by the C8 T1 segments.”³

References

1.

Hong CG, Nam WD. Reliability and Diagnostic Accuracy of Standard Dermatomes and Myotomes for Determining the Pathologic Level in Surgically Verified Patients With Cervical Radiculopathy. Neurospine. 2022;19(4):1006-1012. doi:10.14245/ns.2244194.097

2.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.

3.

Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology. 8th ed. Wolters Kluwer Health; 2022.