Nerve Root Dermatomes, Myotomes, Reflexes and Paresthetic Areas

Dermatome: Medial side of forearm to base of little finger
Muscle Weakness: Lesion at upper two thoracic levels do not appear to give rise to root weakness. Weakness of the hand is due to other pathology
Refexes:
Parasthesias:

Dermatome: Medial side of upper arm to medial elbow, pectoral and midscapular areas
Muscle Weakness: Lesion at upper two thoracic levels do not appear to give rise to root weakness. Weakness of the hand is due to other pathology
Refexes:
Parasthesias:

Dermatome: T3-T6, upper thorax
T5-T7, costal margin
T8-T12, abdomen to lumbar region
Muscle Weakness: Articular and dural signs and root pain are common. Root signs (cutaneous analgesia) are rare and have such indefinite area that they have little localizing value. Weakness is not detectable.
Refexes:
Parasthesias:

Dermatome: Back, over trochanter and groin
Muscle Weakness: None
Refexes: none
Parasthesias: groin; after holding psoture which causes pain

Dermatome: back, front of thigh to knee
Muscle Weakness: psoas, hip adductors
Refexes: none
Parasthesias: occasonally anterior thigh

Dermatome: Back, upper buttock, anterior thigh and knee
Muscle Weakness: psoas, quadriceps, thigh atrophy
Refexes: knee jerk sluggish, PKB ositive, pain on full SLR
Parasthesias: medial knee, anterior lower leg

Dermatome: Medial buttock, lateral thigh, medial leg, dorsum of foot, big toe
Muscle Weakness: Tibialis anterior, extensor hallucis
Refexes: SLR limited, neck flxion pain, weak or absent knee jer, side flexion limited
Parasthesias: medial aspect of calf and ankle

Dermatome: Buttock, posterior and lateral thigh, lateral aspect of leg, dorsum of foot, medial half of sole, first, second, and third toes
Muscle Weakness: extensor hallucis, peroneals, gluteus medius, dorsiflexors, hamstrings and calf athrophy
Refexes: SLR limitied one side, neck flexion painful, ankle decreased, corssed-leg raising pain
Parasthesias: lateral aspect of leg, medial three toes

Dermatome: lateral and plantar aspect of foot
Muscle Weakness: calf and hamstrings, wasting of gluteals, peroneals, plantar flexors
Refexes: SLR limited, achilles reflex weak or absent
Parasthesias: lateral two toes, lateral foot, lateral leg to knee, plantar aspect of foot

Dermatome: Buttock, thigh, posterior leg
Muscle Weakness: same as S1 except peroneals
Refexes: same as S1
Parasthesias: lateral leg, knee, and heel

Dermatome: Groin, medial thigh to knee
Muscle Weakness: none
Refexes: none
Parasthesias: none

Dermatome: perineum, genitals, lower sacrum
Muscle Weakness: bladder, rectum
Refexes: none
Parasthesias: saddle area, genitals, anus, impotence, massive posterior herniation

Dermatome: vertex of skull
Muscle Weakness: none
Refexes: none
Parasthesias: none

Dermatome: Temple, forehead, occiput
Muscle Weakness: longus colli, sternocleidomastoid, rectus capitis
Refexes: none
Parasthesias: none

Dermatome: Entire neck, posterior cheek, temporal area, prolongation forward mandible
Muscle Weakness: trapezius, splenius capitis
Refexes: none
Parasthesias:cheek, side of neck