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Muscle Testing by Cervical Root

Exams and Signs
 

Primary Rami

Root

Ventral

Dorsal

C1Rectus capitis anterior/lateralisRectus capitis posterior major/minor
 Longus capitisObliquus capitis superior/inferior
 GeniohyoidObliquus capitis inferior
 Sternothyroid 
 Thyrohyoid 
 Omohyoid 
C2Rectus capitis anterior/lateralisLongissimus capitis
 Longus capitisSemispinalis capitis
 Longus colliSemispinalis cervicis
 SternocleidomastoidMultifidi
 Sternothyroid 
 Sternohyoid 
 Omohyoid 
C3Intertransversarii cervicisLongissimus capitis
 Longus capitisSplenius capitis
 Longus colliSemispinalis capitis
 SternothyroidSpinalis capitis
 SternohyoidLongissimus cervicis
 OmohyoidSemispinalis cervicis
 Levator scapulae (dorsal)Spinalis cervicis
 Scalenus mediusInterspinales cervicis
 SternocleidomastoidIntertransversarii cervicis (posterior)
 Diaphragm (C4)Rotatores cervicis
 TrapeziusMultifidi
C4Longus colliSplenius capitis
 Intertransversarii cervicis (anterior)Semispinalis capitis
 Levator scapulae (dorsal)Spinalis capitis
 Scalenus anterior/mediusLongissimus cervicis
 Diaphragm (phrenic)Semispinalis cervicis
  Iliocostalis cervicis
  Splenius cervicis
  Spinalis cervicis
  Interspinalis cervicis
  Intertransversarii cervicis (posterior)
  Rotatores cervicis
  Multifidi
C5Longus colliLongissimu capitis
 Intertransversarii cervicis (anterior)Splenius capitis
 Scalenus anterior/mediusSemispinalis capitis
 SubclaviusLongissimus cervicis
 DiaphragmSemispinalis cervicis
 Levator scapulaeIliocostalis cervicis
 Rhomboid majorSplenius cervicis
 Rhomboid minorSpinalis cervicis
 Serratus anteriorInterspinalis cervicis
 Pectoralis major/minorRotatores cervicis
 SupraspinatusMultifidi
 Infraspinatus 
 Subscapularis 
 Teres major/minor 
 Deltoid 
 Coracobrachialis 
 Biceps brachii 
 Brachialis 
 Brachioradialis 
C6Longus colliLongissimus capitis
 Intertransversarii cervicis (anterior)Splenius capitis
 Scalenus anterior/medius/posteriorSemispinalis capitis
 Latissimus dorsiSpinalis capitis
 SubclaviusLongissimus cervicis
 Serratus anteriorSemispinalis cervicis
 Pectoralis major/minorIlocostalis cervicis
 InfraspinatusSplenius cervicis
 SupraspinatusSpinalis cervicis
 SubscapularisInterspinales cervicis
 Teres major/minorIntertransversarii cervicis (posterior)
 DeltoidRotatores cervicis
 CoracobrachialisMultifidi
 Biceps brachii 
 Brachialis 
 Triceps brachii 
 Brachioradialis 
 Anconeuss 
 Supinator 
 Extensor carpi radialis longus 
 Pronator teres 
 Flexor carpi radialis 
C7Intertransversarii cervicis (anterior)Longissimus capitis
 Scalenus medius/posteriorSemispinalis capitis
 Serratus anteriorSpinalis capitis
 Latissimus dorsiLongissimus cervicis
 Pectoralis major/minorSemispinalis cervicis
 CoracobrachialisIlocostalis cervicis
 BrachialisSplenius cervicis
 Triceps brachiiSpinalis cervicis
 AnconeusInterspinales cervicis
 SupinatorIntertransversarii cervicis (posterior)
 Extensor carpi radialis longus/brevisRotatores cervicis
 Extensor carpi ulnarisMultifidi
 Extensor digitorum 
 Extensor indicis 
 Extensor digiti minimi 
 Abductor pollicis longus 
 Extensor pollicis longus/brevis 
 Pronator teres/quadratus 
 Flexor carpi radialis 
 Palmaris longus 
 Flexor carpi ulnaris 
 Flexor pollicis longus 
C8Intertransversarii cervicis (anterior)Longissimus capitis
 Scalenus medius/posteriorSemispinalis capitis
 Latissimus dorsiSpinalis capitis
 Pectoralis major/minorLongissimus cervicis
 Triceps brachiiSemispinalis cervicis
 AnconeusIlocostalis cervicis
 Extensor carpi radialis brevisSplenius cervicis
 Extensor carpi ulnarisSpinalis cervicis
 Extensor digitorumInterspinales cervicis
 Extensor indicisIntertransversarii cervicis (posterior)
 Extensor digiti minimiRotatores cervicis
 Abductor pollicis longusMultifidi
 Extensor pollicis longus/brevis 
 Pronator quadratus 
 Palmaris longus 
 Flexor digitorum superficialis 
 Flexor digitorum profundus 
 Lumbricales 
 Flexor pollicis longus/brevis (deep head) 
 Abductor pollicis brevis 
 Opponens pollicis 
 Adductor pollicis 
 Flexor carpi ulnaris 
 Interossei (dorsal/palmar) 
 Opponens digiti minimi 
 Flexor digiti minimi brevis 
 Palmaris brevis 

 

Grading of muscle strength:

Grade

Strength

Description

  5*

Normal

Completes range of motion and holds against maximal finger resistance

  4*

Good

Completes range against moderate resistance

3

Fair

Completes range of motion with no resistance

2

Poor

Completes range of motion

1

Trace

Palpable or visible contractile activity, which may or may not be accompanied by a flicker of motion

0

Zero

No contractile activity
*The distinction between Grades 4 and 5 is based on comparison with the normal hand and, barring that, extensive experience in testing the hand.
Presentation Photos and Related Diagrams
  • C5 motor activity examined by testing biceps and deltoid muscle.
    C5 motor activity examined by testing biceps and deltoid muscle.
  • C6 motor activity examined by testing biceps and wrist extensor muscle function.
    C6 motor activity examined by testing biceps and wrist extensor muscle function.
  • C7 motor activity examined by testing triceps, wrist flexors and finger extensor muscle function.
    C7 motor activity examined by testing triceps, wrist flexors and finger extensor muscle function.
  • C8 motor activity examined by testing finger flexors and ulnar intrinsic muscle function.
    C8 motor activity examined by testing finger flexors and ulnar intrinsic muscle function.
Definition of Positive Result
  • In muscle testing, a normal result is a positive one. During a normal muscle test, the examiner should observe a normal muscle contraction that can move the joint or tendon against full resistance.
Definition of Negative Result
  • In muscle testing, an abnormal result is a negative one. During an abnormal muscle test, the examiner should observe an abnormal muscle contraction that can move the joint or tendon. In a complete denervation injury, such as a complete nerve laceration, there will be no evidence of any muscle function and the muscle testing grade will be zero.
Comments and Pearls

Quick Root Based Muscle Testing Summary

  • C5 - Elbow Flexion - Test Biceps
  • C6 - Wrist Extension - Test Radial wrist extensors (ECRL & ECRB)
  • C7 - Elbow Extension - Test Triceps
  • C8 - Long Finger Flexion - Test Long finger flexor digitrum profundus (FDP)
  • T1 - Little Finger Abduction - Test hypothenar muscles
Diagnoses Associated with Exams and Signs
References
  1. Hislop JH, Avers D, Brown M. Daniels and Worthingham's Muscle Testing, Techniques of Manual Examination and Performance Testing. 9th ed. St. Louis, Missouri: Elsevier Saunders, 2014, pp. 138–202.
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