Issue 544

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May 16, 2023

Practice Perfect 862
Radiculopathy: The Most Hated (and Missed?) Podiatric Diagnosis Part 2

  Jarrod Shapiro, DPM, FACFAS, FACPM


Ouch, my back hurts, and it’s radiating down my leg! Welcome back to our miniseries on lumbosacral radiculopathy. If you missed last week’s Practice Perfect, I suggest going back for a quick, practical brush up on the important anatomy and pathophysiology of radiculopathy as a cause of foot pain, a commonly missed diagnosis. Today, let’s get right to talking about a high-yield neurological examination to make the diagnosis.

Using Anatomical Knowledge to Make the Diagnosis

Diagnosis of lumbosacral radiculopathy can be very difficult. One important caution is that the muscles of the lower extremity are innervated by nerves arising from multiple nerve roots. As a result, muscle strength loss may be subtle. Diagnosis of radiculopathy is made by a neurological examination including sensory and motor systems, deep tendon reflexes, and localization of pain. Before getting to the neurological examination, one should gather a detailed history, which also includes a review of systems to check for emergent concerns. For example, saddle anesthesia (numbness of the inner thighs and buttocks) is concerning for cauda equina syndrome. Similarly, loss of bowel and/or bladder function or rapidly developing weakness is concerning for an emergent problem. It is also important to consider other less common causes of spinal compression such as tumors of bone or soft tissue, spinal abscesses, a number of infectious diseases, diabetes, and inflammatory disorders (sarcoidosis, chronic inflammatory demyelinating polyneuropathy, and Guillain Barre).

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Since we do not want to miss this diagnosis in podiatry, a good screening lower extremity examination includes tests for radiculopathy, especially in those patients with neuritic pain, radicular pain, or a lower extremity physical examination that does not seem consistent with the history. For example, if a patient first describes a history consistent with plantar fasciitis but the exam shows more diffuse pain, it is prudent to also double check for a radicular cause.

The examination itself should include investigation of the factors noted in Table 1, and results indicating a specific nerve root should lead the examiner to a diagnosis of radiculopathy. For example, a patient with an L5 radiculopathy (the most common type in the lower extremity) may be determined via pain radiating from the back and down the lateral leg to the dorsal foot with weakness of hallux dorsiflexion, numbness to the lateral leg and dorsal foot on the affected side.

For simplicity sake, the table includes the L4 – S2 nerve roots, so you might ask what happened to L1 – L3 and the other Ss? Neurologists commonly think of the L2, 3 and 4 roots together so that makes this more manageable. Additionally, in patients with higher lumbar involvement, we tend to see additional dermatomal involvement above the knee (a big clue during the examination). Similarly, the S2-5 levels more commonly affect the perineum, so we don’t have to worry too much about it. Want to be sure it’s not an S2 level? You can easily check the anal wink reflex, although I’m not sure how many patients going to a podiatrist’s office would expect a rectal exam!

Table 1. Simplified common characteristics of radicular symptoms arising from specific nerve roots.

Root Nerve + Muscle Involved Dermatomal Loss Intermediate Motor Weakness Reflexes
L4 Femoral

Iliopsoas, quadriceps

Hip adductors
Medial calf Hip flexion
Knee flexion
Hip adduction
L5 Peroneal


Superior gluteal
tibialis anterior, peroneals

tibialis posterior

Gluteus medius
Lateral leg, dorsal foot Foot eversion, inversion, dorsiflexion, hip abduction Internal hamstring
S1 Inferior gluteal


Gluteus maximus


Posterior leg, plantar foot Hip extension, knee flexion, ankle plantarflexion Achilles
S2 Inferior gluteal


Gluteus maximus


Sacral, buttock areas, posterior leg,
Minimal weakness, urinary and/or fecal incontinence, sexual dysfunction Bulbocavernosus, anal wink

Putting these findings together and seeing the patterns that arise on the physical examination can lead the astute physician to not just a diagnosis of lumbosacral radiculopathy, but possibly a specific nerve root involvement.

Question: How reliable are common clinical tests to diagnose radiculopathy?

Several maneuvers are used to help determine if a radiculopathy is present, but are these maneuvers actually helpful? IE are they accurate? One might think that combining a number of physical examination tests along with the history would improve our diagnostic accuracy, but unfortunately this is untrue. Finding abnormal reflexes, muscle weakness, sensory abnormalities and a positive straight leg raise test has a low sensitivity, high specificity, and moderate likelihood ratio of 6.001. Keep this in mind the next time you’re “certain” the patient has a radiculopathy – this is actually a challenging diagnosis to make! However, do not discard your careful physical examination. Like every other diagnosis, putting the exam together with a good history is the best way to make that diagnosis.

Supine Straight Leg Raise (SLR) – With the patient lying supine and relaxing the leg, the examiner raises the leg and observes for recurrence of the radicular or dermatomal pain. Flexing the patient’s neck forward is a sensitizing maneuver that may improve accuracy. Similarly, dorsiflexing the foot while raising the leg may also help. This test is specific but not very sensitive for lumbar disk herniation with a small likelihood ratio of 4.732.

Crossed Straight Leg Raise – This modification of the SLR is positive when the uninvolved leg is raised, and the radicular symptoms are noted in the involved side. This test is not sensitive but is highly specific for disc bulging or herniation3.

Slump Test – With the patient sitting and knees bent off the bed, the examiner asks the patient to curve the back while looking straight ahead. The patient then flexes the neck, looking down, while extending the knee. The foot is then dorsiflexed, and a positive result is reproduction of the radicular symptoms. This test has a high sensitivity and specificity for disk bulging or herniation2.

A number of other examination maneuvers are available, but most of them have a lower likelihood ratio, and are beyond the scope of this discussion. I have, for example, found the prone straight leg raise test to be useful when looking for a higher L2-3 level radiculopathy.
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Combining these provocative tests with the above detailed neurological examination and a solid history will significantly increase the chances of coming to a proper diagnosis of lumbosacral radiculopathy, allowing the provider to narrow the spinal level and lead the patient toward comprehensive care and resolution of their disorder.

Best wishes.

Jarrod Shapiro, DPM
PRESENT Practice Perfect Editor
[email protected]

  1. Chapter 4, Thoracolumbar Spine, In Netter’s Orthopaedic Clinical Examination: An Evidence-Based Approach. 2nd edition, 2011. Cleveland and Koppenhaver eds. P. 156.
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  2. Majlesi J, Togay H, Ünalan H, Toprak S. The sensitivity and specificity of the Slump and the Straight Leg Raising tests in patients with lumbar disc herniation. J Clin Rheumatol. 2008 Apr;14(2):87-91.
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  3. Devillé WL, van der Windt DA, Dzaferagic A, Bezemer PD, Bouter LM. The test of Lasegue: systematic review of the accuracy in diagnosing herniated discs. Spine. 2000 May 1;25(9):1140-1147.
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