Straight Leg Raise Test 4 – Common Peroneal Nerve Bias

Purpose of Straight Leg Raise Test 4 – Common Peroneal Nerve Bias: To test if a modified straight leg raise test with a bias towards the peroneal nerve assists in the differential diagnosis of peroneal nerve pathology in people with neurologic symptoms associated with radiculopathy (1, 2).

Patient position: Supine lying.

Examiner position: Standing beside the patient, at the side of the limb to be tested.

Procedure: Perform the limb/joint positioning sequence in the following order:

1. Neutral alignment at the cervical, thoracic and lumbar spine, while the patient is on supine lying,
2. Hip flexion and adduction (to the end of the available range or until the patient reports radicular symptoms), having the knee at full extension (with the examiner’s one hand holding the anterior aspect of the patient’s distal thigh and the other hand holding the posterior aspect of the patient’s ankle),
3. Lower the leg slowly until the radicular symptoms are relieved and hold the leg at this level,
4. Sensitizing position: (a) ankle plantarflexion (3), (b) cervical spine flexion, and/or (c) foot inversion (3).
5. The return of radicular symptoms during ankle plantarflexion, cervical spine flexion, and/or foot inversion with/without further straight leg raise (hip flexion) indicates a positive test.

Alternative Procedure:

In a cadaveric study, Boyd et al. (2) found that the ankle dorsiflexion resulted in medial excursion of the common peroneal nerve while the hip was flexed up to 65 degrees.

To this date, there are however no cadaveric studies that have investigated whether the ankle plantar flexion along with the foot inversion during a modified straight leg raise test can increase strain in the peroneal nerve.

Outcome: This test is positive if (a) the limb/joint positioning sequence reproduces symptoms associated with radiculopathy, (b) the sensitizing position reproduces symptoms, and (c) there is a repeatable and measurable asymmetry between both sides along with the reproduction of symptoms.

Reference:

1. Butler DS, Jones MA, Gore R. Mobilisation of the nervous system: Churchill Livingstone Melbourne etc.; 1991.
2. Boyd BS, Gray AT, Dilley A, Wanek L, Topp KS. The pattern of tibial nerve excursion with active ankle dorsiflexion is different in older people with diabetes mellitus. Clinical Biomechanics. 2012;27(9):967-71.
3. Magee DJ. Orthopedic Physical Assessment: Elsevier Health Sciences; 2013.