Lumbar Root Syndromes

Question 1

L1 root

Answer 1

dermatome:
back, over trochanter, groin

muscle weakness:
none

reflexes/tests:
none

paresthesias:
groin

Question 2

L2 root

Answer 2

dermatome:
back, front of thigh to knee

muscle weakness:
psoas, hip adductor

reflexes/tests:
none

paresthesias:
occasionally front of thigh

Question 3

L3 root

Answer 3

dermatome:
back, upper buttock, front of thigh and knee, medial lower leg

muscle weakness:
psoas, quadriceps - thigh wasting

reflexes/tests:
knee jerks sluggish, pain on full straight leg raise

paresthesias:
inner knee, anterior lower leg

Question 4

L4 root

Answer 4

dermatome:
inner buttock, outer thigh, inside of leg, dorsum of foot, big toe

muscle weakness:
tibialis anterior, extensor hallucis

reflexes/tests:
SLR limited, neck flexion pain, weak knee jerk, side flexion limited

paresthesias:
medial aspect of calf and ankle

Question 5

L5 root

Answer 5

dermatome:
buttock, back and side of thigh, lateral aspect of leg, dorsum of foot, inner half of sole, and first, second, and third toes

muscle weakness:
extensor hallucis, peroneals, gluteus medius, ankle dorsiflexors, hamstrings - calf wasting

reflexes/tests:
SLR limited to one side, neck flexion pain, hamstring reflex decreased, crossed leg-raising pain

paresthesias:
lateral aspect of leg, medial three toes

Question 6

S1 root

Answer 6

dermatome:
buttock, back of thigh, and lower leg

muscle weakness:
calf and hamstrings, wasting of gluteals, peroneals, plantar flexor

reflexes/tests:
SLR limited, decreased ankle jerk

paresthesias:
lateral two toes, lateral foot, lateral leg to knee, plantar aspect of foot

Question 7

S2 root

Answer 7

dermatome:
buttock, back of thigh, and lower leg (same as S1)

muscle weakness:
calf and hamstrings, wasting of gluteals, plantar flexor (same as S1 except peroneals)

reflexes/tests:
SLR limited

paresthesias:
lateral leg, knee, heel

Question 8

S3 root

Answer 8

dermatome:
groin, inner thigh to knee

muscle weakness:
none

reflexes/tests:
none

paresthesias:
none

Question 9

S4 root

Answer 9

dermatome:
perineum, genitals, lower sacrum

muscle weakness:
bladder, rectum

reflexes/tests:
none

paresthesias:
saddle area, genitals, anus, impotence