Review Question - QID 3659

This clinical scenario describes a patient presenting with an L4 radiculopathy. This is supported by his decreased patellar reflex and quadriceps weakness. A L4-5 foraminal (far lateral) herniated nucleus pulposis would most likely cause symptoms in the L4 distribution as foraminal herniations most commonly affect the exiting upper nerve root at a given lumbar level.

Rainville et al performed a study to identify the most sensitive physical exam test to detect quadriceps weakness caused by either an L3 or L4 radiculopathy. They found in L3 and L4 radiculopathies, unilateral quadriceps weakness was detected by the single leg sit-to-stand test in 61%, by knee-flexed manual muscle testing in 42%, by step-up test in 27% and by knee-extended manual muscle testing in 9% of patients. They conclude in L3 and L4 radiculopathies, unilateral quadriceps weakness was best detected by a single leg sit-to-stand test.

Deyo et al review the history, presentation, physical exam findings, and conservative treatment aimed at lumbar disk herniations. They describe the treatment modalities recommended (NSAIDS and early progressive mobilization) and those which are not recommended (narcotics and muscle relaxants). Physical examination maneuvers aimed at ruling out a diagnosis of cauda equina syndrome are imperative to understand and document as cauda equina syndrome is a surgical emergency.

Illustration A shows the location of different types of disk herniations. The red circle shows the location of a foraminal (far lateral) disc herniation. The blue circle shows the location of a paracentral disc herniation. Illustration B shows a T2 axial image of a foraminal (far lateral) disc herniation. Illustration C shows a T2 axial image of a paracentral disc herniation. Illustration D describes the difference between the cervical spine and lumbar spine with respect to nerve root anatomy.