Spinal cord levels

Motor Exam (Myotomes)

Spinal cord tracts

Dermatomes and cutaneous nerves - anterior

Dermatomes and cutaneous nerves - posterior

Lower limb peripheral innervation

• C3-C5: Diaphragm
• C5: Shoulder Abduction
• C5-C6: Elbow Flexion
• C6-C7: Wrist Extension
• C7-C8: Elbow Extension
• C8: Finger Flexion
• T1-T6: Intercostal Muscles
• L3-L4: Thigh Adduction
• L2-L4: Knee Extension
• L4-L5: Ankle Dorsiflexion
• L5-S1: Great Toe Extension
• S1-S2: Ankle Plantarflexion
• S2-S4: Anal Sphincter Contraction

Reflexes

Level	Reflex
C5	biceps
C6	brachioradialis
C7	triceps
L3	quadriceps
S1	achilles tendon
S2,3,4	bulbocavernosus, anal wink

Sensory Exam

• C2 Occiput
• C3 Thyroid Cartilage
• C4 Suprasternal Notch
• C5 Below Clavicle
• C6 Thumb
• C7 Index Finger
• C8 Little Finger
• T4 Nipple Line
• T10 Umbilicus
• L1 Femoral Pulse
• L2-L3 Medial Aspect of Thigh
• L4 Knee
• L5 Lateral Aspect of Calf
• S1 Lateral Aspect of Foot
• S2-S4 Perineal Region

Cervical Exam by Level

Radiculopathy	Motor Deficit	Sensory Deficit	Diminished Reflex
C4	Levator Scapulae & Shoulder elevation
C5	Deltoid & Biceps		Biceps
C6	Brachioradialis & Wrist extension	Thumb Paresthesia	Brachioradialis
C7	Triceps & Wrist flexion	Index/Middle/Ring Paresthesia	Triceps
C8	Index/Middle distal phlnx flexion	Small Finger Paresthesia

See Also

• Sensory exam

References

• Netter's Atlas
• Rosen's 2013, Chapter 43- Spinal Injuries- Tables 43-3,43-4

Authors:

Anand Narayan, Jordan Swartz, Kurt Hansen, Kevin Lu, Michael Holtz, Neil Young, Daniel Ostermayer, Ross Donaldson