| Nerve Root |  |
|
| Dermatome | |
|
| Myotome | |
|
| Reflexes Affected | |
|
| Paresthesias | |
|
| C1 | Vertex of skull | None | None | None |
| C2 | Temple, forehead, occiput | Longus colli, sternocleidomastoid, rectus capitis | None | None |
| C3 | Entire neck, posterior cheek, temporal area, prolongation foreward under mandible | Trapezius, splenius capitis | None | Cheek, side of neck |
| C4 | Shoulder area, clavicular area, upper scapular area | Trapezius, levator scapulae | None | Horizontal band along clavicle and upper scapula |
| C5 | Deltoid area, anterior aspect of entire arm to base of thumb | Supraspinatus, infraspinatus, deltoid, biceps | Biceps, brachioradialis | None |
| C6 | Anterior arm, radial side of hand to thumb and index finger | Biceps, supinator, wrist extensors | Biceps, brachioradialis | Thumb and index finger |
| C7 | Lateral arm and forearm to index, long, and ring fingers | Triceps, wrist flexors (rarely, wrist extensors) | Triceps | Index, long, and ring fingers |
| C8 | Medial arm and forearm to long, ring, and little fingers | Ulnar deviators, thumb extensors, thumb adductors (rarely, triceps) | Triceps | little finger alone or with two adjacent fingers; not ring or long fingers, alone or together (C7) |
| T1 | Medial side of forearm to base of little finger | elbow flexion with arm horizontal, scapulae forward and backward on chest wall, neck flexion | None | None |
| T2 | Medial side of upper arm to medial elbow, pectoral and midscapular areas | Scapulae moving foreward and backward on chest wall, neck flexion | None | None |
| T3-T12 | T3-T6, upper thorax; T5-T7, costal margin; T8-T12, abdomen and lumbar region | None | None | None |
| L1 | Back, over trochanter and groin | None | None | Groin; after holding posture which causes pain |
| L2 | Back, front of thigh to knee | Psoas, hip adductors | None | Occasionally anterior thigh |
| L3 | Back, upper buttock, anterior thigh and knee, medial lower leg | Psoas, quadriceps, thigh atrophy | Knee jerk sluggish, prone knee bend positive, pain on full SLR | Medial knee, anterior lower leg |
| L4 | Medial buttock, lateral thigh, medial leg, dorsum of foot, big toe | Tibialis anterior, extensor hallucis | SLR limited, neck flexion pain, weak or absent knee jerk, side flexion limited | Medial aspect of calf and ankle |
| L5 | Buttock, posterior and lateral thigh, lateral aspect of leg, dorsum of foot, medial half of sole, first, second, and third toes | Extensor hallucis, peroneals, gluteus medius, dorsiflexors, hamstring and calf atrophy | SLR limited one side, neck flexion painful, ankle decreased, crossed-leg raising pain | Lateral aspect of leg, medial three toes |
| S1 | Buttock, thigh, and leg posterior | Calf and hamstring, wasting of gluteals, peroneals, plantar flexors | SLR limited, Achilles reflex weak or absent | Lateral two toes, lateral foot, lateral leg to knee, plantar aspect of foot |
| S2 | Buttock, thigh, and leg posterior | Calf and hamstring, wasting of gluteals, plantar flexors | SLR limited, Achilles reflex weak or absent | Lateral leg, knee, and heel |
| S3 | Groin, medial thigh to knee | None | None | None |
| S4 | Perineum, ganitals, lower sacrum | Bladder, rectum | None | Saddle area, genitals, anus impotence, massive posterior herniation |
