C i.e. L4 -- L5 Disc prolapsed Sudden onset lower back pain with radioculopathy while lifting something heavy from ground (i.e. in spinal flexion) indicates acute PIVD (prolapsed of interveebral disc). Pain or paresthesia along posterolateral aspect of lower thigh, anterolateral aspect of knee and leg and dorsal surface of foot covering great toe, 1st web space upto 3rd MTP joint (but never little toe) indicates compression of L5 nerve root (i.e. prolapsed of L4 --L5 disc). Level of Disc Prolapse Compressed Nerve Root Pain and Sensory Loss Motor Weakness Reflex Affected L3-L4 L4 - Over medial malleous - Ankle dorsiflexion (TA) a/t Knee (quadriceps/patella) (ASIA) - Medial aspect (both anterior ASIA - Knee extension (Quadriceps; jerk | & posterior) of lower thigh, knee, leg (calf) and ankle L4 is main root) - Hip/thigh adduction L4-L5 L5 - Dorsal of foot at 3rd MTP - Great toe extensor (EHL; a/t Knee & Ankle jerks are joint (ASIA) ASIA)Q normal; or knee - Posterolateral buttock (+-) & - Foot eversion (peroneii; paradoxically increased due thigh (esp lower), lateral aspect (anterior > posterior) of knee and leg (calf) and dorsum of foot covering great toe, 1st web space & 3rd main root) - Ankle/foot dorsiflexion (TA) - Toe dorsiflexors - Hip abduction (gluteus medius) to weak knee flexion MTP joint but never little toe. - Knee flexion L5-S1 S1 - Lateral aspect of calcaneus (ASIA) - Lateral aspect of ankle & foot (both on dorsal & plantar aspect) involving lateral malleolus, lateral border of foot & little toe - Ankle & foot plantar flexion (gastrocnemius & soleus; main root; ASIA) - Abductor hallucis (great toe flexion; main root) - Hip extension (gluteus maximus) Ankle jerk |