| 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 |
BIOL3326 Forms
