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!
