| Lumbar Radiculopathy |
| Herniated disc |
90% at L4-L5 & L5-S1, which nerve root is affected
depends on whether the disc herniation is central or lateral |
| Spinal stenosis |
most common at L4-L5 & L3-L4, midsagittal diameter
<10mm |
| Root |
Signs, symptoms |
| L5 |
- Pain: lateral leg to dorsum of foot & big toe
- Weakness: dorsiflexion of foot and toes (tibialis
anterior & ext hallucis longus)
- Reflex change: none
- EMG findings
- Peroneus longus and tensor fascia lata.
Positive in most patients.
- Flexor digitorum longus, tibialis posterior, and tibialis anterior muscles
abnormal in over 75% of the patients.
- Paraspinal muscles, positive in 50%.
- Posterior tibialis or flexor digitorum longus is critical, as these are the only L5 innervated muscles below the knee not innervated by the peroneal nerve.
|
| S1 |
- Pain: back of calf to lateral foot & little
toe
- Weakness: plantar flexion and eversion of foot.
- Reflex change: ankle jerk
- EMG findings:
- Biceps femoris short head and long head, and medial gastrocnemius.
Exclusively innervated by the S1 root, involved in > 80% of
patients:
- Paraspinal
muscles. 25%
of patient shows abnormalities.
- Other S1 muscles: abductor
hallucis, gluteus maximus
|
| L4 |
- Pain: back pain down to knee and to medial malleolus
- Weakness: inversion of foot
- Reflex change: knee jerk
|
| L3 |
- Pain: across thigh
- Weakness: knee extension, thigh adduction
- Reflex change: adductor reflex
|
| L2 |
- Pain: across thigh
- Weakness: hip flexion, adduction
- Reflex change: none
|
|
|
