Source: Robert E. Sallis, MD. Kaiser Permanente, Fontana, California, USA
The back is the most common source of pain in the body. Examination of the back can be a challenge due to its numerous structures, including the bones, discs, ligaments, nerves, and muscles-all of which can generate pain. Sometimes, the location of the pain can be suggestive of etiology. The essential components of the lower back exam include inspection and palpation for signs of deformity and inflammation, evaluation of the range of motion (ROM) of the back, testing the strength of the muscles innervated by the nerves exiting in the lumbar-sacral spine, neurological evaluation, and special tests (including the Stork test and Patrick's test).
Inspection should be done with the patient standing, while observing from behind. Have the patient remove enough clothing so the entire back and sacral area can be properly inspected.
- Inspect the entire back for redness, asymmetry, deformity, scoliosis, or abnormal hair growth.
- From the side, observe lumbar lordosis, which normally appears as a gentle, reverse C-shaped curve of the spine.
Palpate for areas of tenderness. Important areas to check include:
- Spinous processes: These are the hard bony structures that run down the midline of the back. Look for a step-off at L4-S1, which is suggestive of spondylolisthesis.
- Paraspinous muscles: These are the muscles that run along either side of the spinous processes and are often tender with overuse of the back.
- Sacroiliac (SI) joint: Palpate below and lateral to the posterior superior iliac spine.
- Sciatic notch: The sciatic notch is located midway between the posterior superior iliac spine (which is the posterior tip of the iliac crest) and ischial tuberosity. Push here to aggravate pain caused by sciatica.
- Iliac crests: Place your hands on both iliac crests, and compare their height. If one hand sits higher than the other, it may suggest leg length inequality or scoliosis.
3. Range of Motion (ROM)
Evaluate the ROM of the back. Look for deficits or excessive pain. Key motions include:
- Forward flexion (normally 80-90°): To evaluate, have the patient bend forward to touch the toes. This loads the discs, which makes it more likely to increase disc pain. Be sure to observe from behind when the patient is bent forward to look for asymmetry of the back, which is suggestive of scoliosis.
- Extension (20-30°): Have the patient bend straight backward as far as possible. This loads the facets, which makes it more likely to increase facet pain.
- Lateral bending (20-30° in each direction): Assess by having the patient bend, first to one side and then the other. This stretches the muscles and is more likely to aggravate pain from muscle strain.
- Twisting (30-40° in each direction): Have the patient (standing) rotate as far as possible, first to one side and then the other. This also stretches the muscles and increases pain from the source.
4. Strength Testing
Evaluate the strength of the muscles innervated by the key nerve roots exiting in the lumbar-sacral spine. Weakness suggests irritation of these nerve roots from disc or bony pathology. These include:
- Heel walking (anterior tibial muscles; L4): Ask the patient to walk a few steps on the heels.
- Toe walking (gastrocnemius soleus muscles; S1): Ask the patient to walk a few steps on the toes.
- Resisted great toe dorsiflexion (L5): Ask the patient to sit and lift the big toe up against your resistance, pressing down on the top of the toe.
5. Neurologic Exam
Conduct a focused neurologic exam in patients with lower back pain.
- Deep tendon reflexes (knee jerk - L4 nerve root; ankle jerk - S1 nerve root): Tap a reflex hammer briskly against the patella and Achilles tendons, comparing side to side.
- Ankle clonus: Elicit ankle clonus by sudden passive ankle dorsiflexion, which may result in repetitive and uncontrolled ankle twitches. This suggests an upper motor neuron lesion, such as proximal spinal cord compression.
- Straight-leg raise: Lift the patient's leg, with the knee extended, in the sitting (or supine) position. Pain radiating past the knee suggests sciatica, likely caused by disc herniation in the lumbar-sacral area (L5 and S1 nerve roots). Dorsiflexion of the ankle during the straight-leg raise test increases sciatic tension and pain, while plantar flexion relieves sciatic tension and pain.
- Crossed straight leg raise: Do a straight-leg raise test on the opposite, uninvolved leg. If this maneuver aggravates the pain in the opposite leg, it is suggestive of sciatica.
- When cauda equina syndrome is suspected, consider a rectal exam to check for decreased sphincter tone and perianal sensation.
6. Special Tests
Special tests in the back include:
- Stork test (one-leg standing hyperextension test): Have the patient hyperextend the back while standing on one leg. This position aggravates pain associated with spondylolysis, spondylolisthesis or SI joint dysfunction.
- Patrick's or the flexion, abduction, and external rotation (FABER) test: Place the patient's hip and leg into the figure-of-four position (flexion, abduction, and external rotation). This position aggravates SI joint pain.
The lower back region is one of the most common sources of pain in the human body. However, examination of this region can be a challenge due to its numerous structures -including several bones, discs, nerves, ligaments, and muscles - all of which can generate pain.
This video will focus on the essential components of the lower back exam, which include inspection, palpation for signs of deformity and inflammation, evaluation of the range of motion, testing the strength of the muscles innervated by the nerves exiting in the lumbar-sacral spine, neurological evaluation and a couple of special tests.
Let's begin with inspection and palpation. Before you start, wash your hands thoroughly. Ask the patient to remove sufficient clothing, stand straight and turn their back to you. Carefully inspect the entire area for redness, asymmetry, deformity, scoliosis or abnormal hair growth. Next, have your patient turn to one side so you can observe lumbar lordosis, which normally appears as a gentle C-shaped curve of the spine.
After inspection, begin with palpation. Start at the spinous processes, these are the hard bony structures that run down the posterior midline. Palpate for tenderness and step-off. Also, palpate the paraspinous muscles, which runs along the sides of the spinous processes. Tenderness in muscles may suggest overuse of the back. Next, place your index fingers on the iliac crest and move your thumbs across to the center to specifically palpate the L4-L5 disc space, and below that would be the L5-S1 space. Next, to palpate the sacroiliac joint, first locate the posterior superior iliac spine, and slightly below and medial to that is the sacroiliac joint. Then transition to the sciatic notch, which is located midway between the posterior superior iliac spine and ischial tuberosity. Apply moderate pressure to the area. Pain experienced by the patient may suggest sciatica. Lastly, place your hands on the patient's iliac crests and compare their locations. If one hand sits higher than the other, it may suggest leg length inequality or scoliosis.
After inspection and palpation, move onto testing the back's range of motion. While doing so, look for deficits or excessive pain. Begin with forward flexion. Have the patient bend forward to touch their toes. This loads the discs, which makes it more likely to increase disc pain. The normal range of motion for forward flexion is about 80° to 90°. Be sure to observe from behind when the patient is bent forward to look for asymmetry of the back suggestive of scoliosis.
Next, test extension by having the patient bend straight backwards as far as possible. Normally, this would be about 20° to 30°. Then assess lateral bending by having the patient bend to one side and then the other. This stretches the muscles and is more likely to aggravate pain from muscle strain. Normally, one should be able to bend by 20-30° in each direction.
Lastly, test the ability to twist. Ask the patient to stand straight and rotate as far as they can go on one side and then the other. The normal range of motion for this movement is 30°to 40° in each direction.
Following range of motion tests, evaluate the strength of the muscles innervated by the key nerve roots exiting in the lumbar-sacral spine. Weakness suggests irritation of these nerve roots from disc or bony pathology.
For the first strength test, ask the patient to walk a few steps on their heels. This will assess the anterior tibial muscles innervated by L4. Next, ask the patient to walk a few steps on their toes to test the gastrocnemius soleus muscles and the corresponding S1 innervation. Lastly, ask the patient to sit on the examination table. Then instruct them to lift their big toe as you apply resistance by pressing it down. This examines the L5 nerve root.
Following the strength tests, if the patient is experiencing lower back pain, you should conduct a focused neurological examination.
Start with the deep tendon reflex test. With the patient in seated position, tap the reflex hammer briskly against the patella tendon and then the Achilles tendon, looking for a quick contraction of the muscle proximal to that tendon. Compare both sides and note your results.
Next, assess for ankle clonus. Grab the patient's foot and elicit sudden, passive dorsiflexion. Any subsequent repetitive and uncontrolled ankle twitches, which are absent here, may suggest an upper motor neuron lesion.
Subsequently, perform the straight-leg raise test by elevating the patient's leg with the knee extended. Pain radiating past the knee may suggest sciatica likely caused by disc herniation in the lumbar-sacral area. Dorsiflexion of the ankle during the straight-leg raise test increases the sciatic tension and pain, while plantar flexion relieves the tension and the associated pain.
Then, conduct a crossed straight-leg raise test by elevating the patient's opposite leg with the knee extended. Pain experienced by the patient in the non-elevated leg may be a further sign of sciatica.
After performing all the above-mentioned maneuvers, evaluate the back by conducting a couple of special tests. First of these is the Stork test. Have the patient stand on one leg and hyperextend their back. If the patient experiences pain, it may suggest spondylolysis, spondylolisthesis and/or SI joint dysfunction.
Lastly, conduct the Patrick's test. Have the patient transition into supine position. Instruct the patient to put their right ankle above their left knee forming a figure-four position, then push shown on the bent knee. Pain with this maneuver may suggest SI joint injury. This test is also known as the FABER test as it assesses flexion, abduction, and external rotation simultaneously.
You have just watched a JoVE Clinical Skills video article on the lower back examination. The presentation reviewed the essential aspects of this exam including inspection, palpation, range of motion, strength testing, neurological exam, and additional special diagnostic maneuvers to narrow down differential diagnosis related to the commonly encountered back pain. As always, thanks for watching!
Applications and Summary
Low back pain is very common, and occasionally can be a manifestation of a serious underlying condition, such as cancer, infection, or a surgical emergency. Systematic physical examination supplements the information obtained in the history by helping to identify serious problems that require earlier clinical actions or neurological dysfunction. Examination of the lower back is best done with the patient in both sitting and standing positions, following a step-by-step approach. It is important to have the patient remove enough clothing so the surface anatomy can be easily seen and evaluated. The exam begins with inspection, looking for asymmetry or deformity. This is followed by palpation, looking for tender spots or an abnormal step-off between the vertebrae. Next is an assessment of ROM, looking for pain or limitation in motion. From there, an evaluation can be made for lumbar nerve problems by assessing strength and the deep tendon reflexes, and conducting the straight-leg raise. This is followed by special tests, including the Stork test and the FABER test.