Lumbar Radiculopathy B&B Flashcards
radiculopathy
compression of nerve root at the spine
what are the outer fibrous ring and the soft center of the intervertebral disc called, respectively?
outer fibrous ring = annulus fibrosus
soft center = nucleus pulposus
what occurs in a herniated disc?
most common cause of radiculopathy
degeneration of annulus fibrosis (outer ring) with bulging/extrusion of nucleus pulposus (soft center)
usually occurs posteriorly because the posterior longitudinal ligament is weaker than the anterior longitudinal ligament
affects the nerve root below the disc
what occurs in spondylolisthesis?
forward displacement (slippage) of one vertebrae over another, may cause radiculopathy
spondylo = vertebrae/spine
listhesis = movement
spondylosis = degeneration of spinal column
why does spinal stenosis occur with age?
intervertebral discs shrink (narrowing their foramen) + facet joint arthritis (causing bone spurs) + ligamentum flavum hypertrophy (causing nerve compression)
nerve compression (radiculopathy) is worse standing straight because this narrows the lumbar canal
what is the cause of neurogenic claudication?
leg pain with walking, due to spinal stenosis
how can neurogenic claudication be differentiated from vascular claudication?
neurogenic claudication (due to spinal stenosis) persists with rest and improves with stooped posture
recall standing straight narrows the lumbar canal
what is the motor function of the sciatic nerve (L4-S3), before it branches into the common peroneal and tibial nerves?
muscles of posterior thigh:
1. hamstrings - semimembranosus (medial) + semitendinosus + biceps femoris (lateral)
2. adductor magnus - medial thigh muscle with a portion similar to the hamstrings
—> knee flexion, hip extension, hip rotation
where is the pain associated with sciatica felt?
sciatica = pain of lumbar radiculopathy
low back —> buttocks —> back of thigh
commonly caused by herniated disc
how could sciatic neuropathy occur?
for total sciatic neuropathy, injury must occur past the point where L4-S3 conjoin in sciatic nerve
commonly hip fracture or dislocation because sciatic nerve is behind the hip joint, or prolonged compression (coma/bed rest)
if severe - hamstring weakness, loss of dorsiflexion/foot drop (common peroneal nerve), sensory loss in lower leg/foot (tibial nerve)
what is the most common nerve root affected by herniated disc, and what symptoms does this cause?
L5 (due to herniated disc above)
—> pain down Lateral leg, weak foot dorsiflexion and toe extension (difficulty walking on heels)
this is because many of L5 fibers contribute to common peroneal nerve
what symptoms are associated with compression of S1 nerve root by herniated disc?
pain down back of leg, weak plantar flexion (difficulty standing on toes), absent ankle reflex
this is because many S1 fibers supply tibial nerve, which innervates muscles of foot responsible for plantar flexion
Two patients present with a herniated disc. Patient 1 has difficulty walking on their heels, while Patient 2 has difficulty walking on their toes. Which vertebrae are mostly likely affected in each patient? Explain.
Patient 1: L5 (L4/L5 herniated disc) —> pain down Lateral leg, weak foot dorsiflexion and toe extension (difficulty walking on heels)… this is because many of L5 fibers contribute to common peroneal nerve
Patient 2: S1 (L5/S1 herniated disc) —> pain down back of leg, weak plantar flexion (difficulty standing on toes), absent ankle reflex… this is because many S1 fibers supply tibial nerve, which innervates muscles of foot responsible for plantar flexion
what symptoms are associated with radiculopathy of L2/L3/L4, such as by a herniated disc? why does this make sense?
higher nerve roots —> thigh/knee symptoms
pain to anterior thigh/knee, weakness of hip flexion and knee extension, reduced patellar reflex
this makes sense because L2-L4 supply femoral nerve
Lasegue’s sign
worsening pain with straight leg raise test, positive for lumbar radiculopathy
due to stretching of sciatic nerve (L4-S3) and nerve roots
