8.1 Orthopedic Examination: Lumbar Spine and Pelvis

8.1 Orthopedic Examination: Lumbar Spine and Pelvis

Neuromusculoskeletal Diagnosis is the largest clinical domain on NBCE Part II, and lumbar spine and pelvic special tests appear constantly because they pair a recognizable maneuver with a specific anatomic structure. The boards rarely ask you to perform an entire examination; instead, a vignette describes hip flexion with knee extension, compression of the SI joint, or extension-quadrant loading and asks which test was done, what structure is stressed, or what diagnosis a positive result supports. Your task is to know the named test, the direction of stress, and whether the pain pattern is axial (joint or ligament), radicular (nerve root), or referred (visceral or hip). Confusing disc herniation with sacroiliac dysfunction, or L5 radiculopathy with hip osteoarthritis, is one of the most common Part II traps.

How Lumbar and Pelvic Tests Work

Orthopedic special tests mechanically load a single structure — disc annulus, nerve root, facet capsule, sacroiliac ligament, or hip joint — and a positive test reproduces the patient's familiar pain, provokes radicular symptoms, or reveals instability. No isolated test is definitive; clinicians cluster findings with history, neurologic screening, and imaging. On the NBCE, however, you need the textbook one-to-one pairing. Two concepts recur: sensitivity (a negative result helps rule out disease) and specificity (a positive result helps rule in disease). The straight leg raise is sensitive for nerve root irritation; the crossed straight leg raise is far more specific for disc herniation because it is positive in only a minority of patients but strongly predicts surgical disc pathology when present.

Nerve Root and Disc Tests

Straight leg raise (Lasègue test)

With the patient supine, the examiner passively flexes the hip with the knee extended. Pain radiating below the knee before reaching approximately 60 degrees of hip flexion is positive for lumbar nerve root irritation, most often from disc herniation at L4–L5 or L5–S1. Local hamstring tightness causing posterior thigh pain that does not cross the knee is not a positive Lasègue for radiculopathy — that distinction is a classic trap.

Crossed straight leg raise

Raising the asymptomatic leg reproduces pain in the symptomatic leg. This test is highly specific for disc herniation (low sensitivity), and its presence strongly supports a compressive radiculopathy over facet pain or muscular strain.

Femoral nerve stretch test (reverse Lasègue)

With the patient prone, the examiner extends the hip while keeping the knee flexed. Anterior thigh pain suggests L2–L4 nerve root or femoral nerve irritation. Students often apply this test to L5–S1 disc cases — that is incorrect anatomy. L5 radiculopathy classically presents with dorsifoot pain and SLR positivity, not anterior thigh pain.

Bragard sign

After a positive SLR at a limited angle, the examiner dorsiflexes the ankle. Increased radicular pain confirms nerve root tension beyond simple hamstring tightness.

Facet and Posterior Element Tests

Kemp test (extension quadrant)

Standing or seated, the patient extends and laterally bends toward the painful side. Reproduction of unilateral low-back pain suggests facet joint arthropathy or posterior element stress. Radicular pain worsened by flexion (not extension) points toward disc pathology instead.

Yeoman test

Prone with the knee flexed to 90 degrees, the examiner lifts the thigh into extension while stabilizing the pelvis. Pain in the buttock or SI region suggests sacroiliac joint or hip flexor involvement; lumbar pain may indicate facet irritation.

Sacroiliac and Pelvic Tests

The key trap: FABER pain in the groin localizes to the hip (labrum, FAI, OA); FABER pain below the PSIS suggests the sacroiliac joint. Bilateral SI pain after pregnancy or trauma should raise suspicion for ligamentous laxity or inflammatory spondyloarthropathy, not isolated muscular strain.

Hip versus Lumbar Differentiation

• Thomas test: Supine, one knee pulled to chest; opposite thigh should remain flat. Hip flexion off the table indicates a fixed hip flexion contracture (iliopsoas tightness), which can mimic lumbar hyperlordosis.
• Ober test: Side-lying hip abduction and extension; failure to adduct indicates ITB tightness, often contributing to pelvic obliquity and compensatory lumbar pain.
• FADIR test: Hip flexion, adduction, internal rotation reproduces groin pain in femoroacetabular impingement or labral tears — a frequent mimic of anterior hip and SI pain.

Lumbar Dermatomes for Part II

Knowing dermatomes lets you match sensory complaints to nerve roots:

Part II Traps and Vignette Patterns

Expect stems that describe the maneuver without naming it: "The examiner passively raises the straight leg and the patient reports pain shooting to the lateral foot below the knee at 40 degrees" (positive SLR, L5/S1 radiculopathy). Watch for cauda equina red flags hidden inside orthopedic vignettes — bilateral leg pain, saddle anesthesia, bowel or bladder dysfunction — which override any special-test interpretation and demand emergency referral. Do not confuse central stenosis (neurogenic claudication relieved by flexion, such as shopping-cart sign) with vascular claudication (relieved by standing still, absent pulses, skin changes). Finally, remember that a negative SLR does not exclude disc pathology (sensitivity is not 100%), but a positive crossed SLR is one of the strongest clinical predictors of disc herniation on Part II.