A physical therapist is evaluating a patient with low back pain radiating into the left posterior thigh and calf. A straight leg raise on the left side reproduces the patient's familiar symptoms. When the therapist performs a crossed straight leg raise on the right leg, the patient again experiences pain radiating down the left leg. What is the MOST appropriate interpretation of these findings?

1. The patient has bilateral hamstring tightness
2. The patient has non-specific low back pain unrelated to nerve root involvement
3. The symptoms are due to sacroiliac joint dysfunction on the left side
4. The findings suggest a large central disc herniation compressing a nerve root

Transcript

Welcome back to the Scorebuilders' Question and Answer Podcast! This podcast provides members of the Scorebuilders' team with the opportunity to explore challenging multiple-choice examination questions with students actively preparing for the licensing examination.

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A physical therapist is evaluating a patient with low back pain radiating into the left posterior thigh and calf. A straight leg raise on the left side reproduces the patient's familiar symptoms. When the therapist performs a crossed straight leg raise on the right leg, the patient again experiences pain radiating down the left leg. What is the MOST appropriate interpretation of these findings?

1. The patient has bilateral hamstring tightness
2. The patient has non-specific low back pain unrelated to nerve root involvement
3. The symptoms are due to sacroiliac joint dysfunction on the left side
4. The findings suggest a large central disc herniation compressing a nerve root

Straight Leg Raise

The straight leg raise (SLR) is one of the most commonly performed neurodynamic tests in physical therapy. It is used to assess for lumbar nerve root irritation or compression by placing tension on the sciatic nerve and its contributing nerve roots.

Crossed Straight Leg Raise

The crossed straight leg raise (CSLR) takes this one step further. In this test, the clinician raises the UNAFFECTED leg and a positive test occurs when symptoms are reproduced in the OPPOSITE, affected leg. That's the key concept here. We're moving the right leg, but the patient feels it in the left leg. That's a very telling clinical finding.

This question is really testing whether you understand what a positive CSLR means and why it's clinically significant. Think about what could possibly cause symptoms to radiate down one leg when the other leg is being moved. 

Let's explore each of the options:

Option 1 - The patient has bilateral hamstring tightness

Hamstring tightness is a very common finding in patients with low back pain. When you stretch a tight hamstring, where do you feel it? Tightness is felt in the leg being stretched - not in the opposite leg. Hamstring tightness cannot explain why raising the right leg produces symptoms in the left leg. This option can be eliminated quickly.

Option 2 - The patient has non-specific low back pain unrelated to nerve root involvement

Non-specific low back pain is a broad category that describes localized back discomfort without a clearly identified structural cause. It typically presents as pain in the back itself, maybe with some local muscle guarding or stiffness. Here's the problem with this option - our patient has symptoms radiating all the way down the posterior thigh and into the calf. That's a radicular pattern and those symptoms are being reproduced by neural tension tests. Non-specific low back pain doesn't behave this way. This option doesn't fit the clinical picture.

Option 3 - The symptoms are due to sacroiliac joint dysfunction on the left side

Sacroiliac joint dysfunction is another common cause of low back and buttock pain, and it can occasionally refer pain into the upper thigh. SI joint dysfunction does not produce true radicular symptoms extending down to the calf, and it is not provoked by neural tension tests like the CSLR. If this were SI joint dysfunction, we'd expect localized pain in the posterior pelvis or buttock region, not symptoms radiating down the leg when we lift the opposite limb. This option doesn't fit either.

Option 4 - The findings suggest a large central disc herniation compressing a nerve root

When a disc herniates centrally, it can compress nerve roots on both sides of the spinal canal. When we raise the unaffected leg, it shifts the spinal cord and nerve roots slightly within the canal, placing tension on the compressed nerve root on the opposite side and reproducing symptoms. The combination of a positive ipsilateral straight leg AND a positive crossed straight leg raise is a powerful clinical finding. It tells us this isn't just a minor nerve root irritation - this is significant compression, most likely from a large central disc herniation.

Boom- the clinical picture is clear! The correct answer is Option 4.

Let's explore the all student data:
2% of students selected Option 1 - The patient has bilateral hamstring tightness
5% of students selected Option 2 - The patient has non-specific low back pain unrelated to nerve root involvement
13% of students selected Option 3 - The symptoms are due to sacroiliac joint dysfunction on the left side
80% of students selected Option 4 - The findings suggest a large central disc herniation compressing a nerve root - the correct response

System Classification
This question is a Neuromuscular and Nervous Systems question which represents approximately 24% of all exam items.

Content Outline Classification
This question is a Physical Therapy Examination question which represents approximately 24% of all exam items.

Level Classification
This question is a Level 1 question since the question requires students to possess basic foundational academic knowledge. Remediation of Level 1 questions occurs through academic review of entry-level content using textbooks, review books, Basecamp, and flash cards.

Thanks for joining us on the Scorebuilders Q&A podcast! See you next week!