Kemp’s test is a common orthopedic assessment used by healthcare providers to evaluate the lower back, or lumbar spine. This provocative test is designed to elicit a patient’s familiar pain symptoms. By physically manipulating the spine, the test helps a clinician narrow down the potential source of a patient’s back pain, particularly whether the pain originates from the small joints in the spine or from nerve root irritation.
Performing the Kemp’s Test Maneuver
The test is most commonly performed with the patient standing, though a seated variation also exists, with the examiner positioned behind the patient for support and control. The primary goal of the maneuver is to put maximum stress on the posterior elements of the spine, specifically the facet joints and the intervertebral foramina. The examiner begins by placing one hand to stabilize the patient’s lumbar region and using the other hand to guide the movement from the shoulder or upper back.
The patient is first gently guided into extension, which involves leaning the body backward, placing initial compression on the facet joints. While maintaining this extension, the examiner then introduces lateral flexion, or side-bending, followed by rotation, all toward the side of the patient’s reported pain. This combination of movements—extension, lateral flexion, and rotation—is performed slowly and deliberately to gradually increase the mechanical load on the lumbar structures.
This specific, multi-planar motion mechanically narrows the space where spinal nerves exit the vertebral column, known as the intervertebral foramen. The movement also maximally compresses the facet joints on the side the patient is bending and rotating toward. The patient is asked to report any reproduction or intensification of their pain during this gradual, compounding movement, which helps the clinician correlate the mechanical stress with the patient’s symptoms.
Interpreting Positive and Negative Outcomes
The interpretation of a positive Kemp’s test depends entirely on the quality and location of the pain it reproduces. One primary positive finding is pain that remains localized to the lower back, often described as a sharp ache near the spine, which suggests facet joint dysfunction. This localized pain indicates that the compression and stress on the posterior joints is the likely source of the symptoms. Facet joint irritation, also called facet syndrome, often involves degenerative changes or inflammation in these small stabilizing joints.
A different type of positive finding is the reproduction of radicular pain, which is an electric, shooting, or burning pain that travels away from the back and down into the leg. This radiating symptom strongly suggests nerve root compression or irritation, which may be caused by a disc herniation or spinal stenosis. The maneuver’s action of narrowing the intervertebral foramen mechanically irritates the nerve root, causing the pain to follow the nerve’s pathway into the lower extremity.
A negative outcome is recorded if the patient feels no pain or only a general, non-specific discomfort that does not match their primary complaint. A negative result may help a clinician eliminate the facet joint as a significant source of pain. However, the overall diagnostic accuracy of the Kemp’s test alone is considered limited in current literature.
Clinical Role in Diagnosing Lower Back Pain
Kemp’s test functions as a provocative assessment, meaning its purpose is to provoke symptoms to gather information, rather than to provide a definitive diagnosis. Clinicians use it as one tool in a comprehensive battery of orthopedic and neurological tests performed during a physical examination. The results help the practitioner form a differential diagnosis, which is a list of possible conditions causing the patient’s pain.
The information gathered from this test helps distinguish between purely musculoskeletal pain and symptoms that involve neurological structures. For instance, a positive Kemp’s test with radicular pain, when considered alongside other findings like a positive Straight Leg Raise test, strengthens the suspicion of a disc-related nerve issue. Conversely, localized pain without radiation points toward structural issues within the spine, such as mechanical lower back pain or facet joint involvement.
Because of its moderate sensitivity and specificity, the test cannot reliably confirm or exclude a condition by itself. Its value lies in providing contextual evidence that guides the clinician toward further, more specific testing or imaging. The test serves as a practical, in-office method to help narrow the focus of an examination, moving the process forward from a general complaint of back pain to a more specific working diagnosis.