Dermatomes, Myotomes

vertex of skull

temple, forehead, occiput

entire neck, posterior cheek, temporal area, prolongation forward under mandible

shoulder area, clavicular area, upper scapular area

deltoid area, anterior aspect of entire arm to base of thumb

Anterior arm, radial side of hand to thumb and index finger

Lateral arm and forearm to index, long, and ring finger

medial arm and forearm to index, long, and ring fingers

medial side of forearm to base of little finger

medial side od upper arm to medial elbow, pectoral and midscapular areas

• T3-T6 upper thorax
• T5-T7 costal margin
• T8-T12 abdomen and lumbar region

back, over trochanter and groin

back, front of thigh to knee

back, upper buttock, anterior thigh and knee, medial lower leg

Medial buttock, lateral thigh, medial leg, dorsum of foot, big toe

none

longus colli, sternocleidomastoid, rectus capitis

Trapezius, splenius capitis

Trapezius, levator scapulae

supraspinatus, infraspinatus, deltoid, biceps

biceps, supinator, wrist extensors

triceps, wrist flexor

Ulnar deviators, thumb extensors, thumb adductors

disk lesions at upper two thoracic levels and intrinsic muscles

weakness not detectable

none

psoas, hip adductors

psoas, quadricps, thigh atrophy

Tibialis anterior, extensor hallucis

buttock, posterior and lateral thigh, lateral aspect of leg, dorsum of foot, medial half of sole, first, second, and third toes

buttock, thigh, and leg posterior

buttock, thigh, and leg posterior

groin, medial thigh to knee

perineum, genitals, lower sacrum

extensor hallucis, peroneals, gluteus medius, dorsiflexors, hamstring and calf atrophy

calf and hamstrings, wasting of gluteals, peroneals, plantar flexors

calf and hamstrings, wasting of gluteals, plantar flexors

none

bladder, rectum