Axiom: In the setting of trauma or neurologic deficit, any motion in the spine should be avoided until after imaging to evaluate spinal stability.
The examination of a patient with back pain begins with an assessment of the vital signs. Although hypertension should raise the suspicion for aortic dissection, hypotension in the presence of back pain suggests an abdominal aortic aneurysm until proven otherwise. In the setting of trauma with spinal cord injury, consider neurogenic shock as a possible cause of hypotension once hemorrhage has been excluded. A fever is important to note; however, its absence does not exclude a significant infection. For example, one-half of patients with pyogenic osteomyelitis do not have fever.13
A complete physical examination should be performed with particular attention to the heart, pulses, lungs, abdomen, and skin, followed by detailed musculoskeletal and neurological examinations. Decreased breath sounds may suggest a malignancy-related effusion; rales or rhonchi may suggest pneumonia or other active infection. Cardiovascular examination including peripheral pulse examination should be completed to assess for asymmetry of peripheral pulses or upper-extremity blood pressures, which would raise concern for aortic dissection. The abdominal examination should assess for the presence of a pulsatile mass, which would suggest an abdominal aortic aneurysm. It is important to perform a rectal examination in order to assess for loss of rectal tone or perianal anesthesia, especially when cord compression is considered on the differential. A thorough examination of the skin may reveal evidence of the early lesions of herpes zoster. Neurological examination should include full assessment of strength, sensation, and reflexes, as well as rectal tone and perianal sensation in appropriate patients. Further discussion of neurological and musculoskeletal examinations is detailed below.
Cervical Spine Examination
Inspection starts by looking for scars, ecchymoses, or erythema. In the nontraumatic setting, the normal lordosis of the cervical spine is best seen from the side of the patient. If Valsalva or compression on the top of the head reproduces pain, there is likely a herniated disk or spinal stenosis affecting the diameter of the spinal canal or foramina.
In the cervical spine, the muscles are relaxed in the supine position, making the deeper bony and ligamentous structures more readily palpable in this position. The examiner begins by feeling the occiput and the base of the skull in the midline. The posterior bony structures are best palpated if the examiner stands behind the patient’s head and cups the hands under the neck so that the fingertips meet at the midline (Fig. 7–4). The first structure noted is the spinous process of the axis (C2). The posterior arch of C2 is not palpable. In the thin patient, the examiner should be able to feel all the spinous processes of the cervical spine. Loss of alignment is seen in unilateral facet joint dislocation or with a fracture.
Examine the posterior cervical spine from behind the patient’s head with the hands cupped so that the fingertips meet at the midline.
C7 (and sometimes T1) has the largest spinous process in most individuals and is a helpful landmark. Other landmarks in the cervical spine include the thyroid cartilage, which overlies C4 and C5, and the cricoid cartilage that is at the level of C6. The facet joints are palpated lateral to and between the spinous processes on each side. In the relaxed neck, they feel like a small dome. Tenderness over the facet joints suggests arthritis, fracture, or ligamentous injury.
The neurologic examination should include an assessment of motor strength, sensation, and reflex testing. The location of cord injury can be determined by knowing how-to-test function at that level. In the cervical spine, C5 to C8 are most commonly affected (Table 7–4 and Figs. 7–5 to 7–8).
TABLE 7-4Physical Examination to Test the Cervical Nerve Roots ||Download (.pdf) TABLE 7-4 Physical Examination to Test the Cervical Nerve Roots
| ||C5 ||C6 ||C7 ||C8 |
|Sensory ||Lateral arm ||Lateral forearm and thumb ||Middle finger ||Ulnar forearm or little finger |
|Motor ||Shoulder abduction and elbow flexion ||Elbow flexion and wrist extension ||Elbow extension and wrist flexion ||Finger flexion |
|Reflex ||Biceps ||Brachioradialis ||Triceps ||None |
Neurologic assessment of the C5 nerve root.
Neurologic assessment of the C6 nerve root.
Neurologic assessment of the C7 nerve root.
Neurologic assessment of the C8 nerve root.
Thoracolumbar Spine Examination
The thoracolumbar examination should proceed in a systematic manner for both efficiency and completeness. The complete examination of the spine in the nontraumatized patient will be reviewed in this section, but depending on the clinical scenario, the clinician will not need to perform all of the maneuvers described.
If the patient is able to stand, the examination begins in this position with inspection. Note the normal lordosis of the lumbar spine. Straightening of the lumbar spine might suggest ankylosing spondylitis or paravertebral muscle spasm. Next, check the alignment of the back from behind the patient. Over half of patients will have abnormalities of alignment that may contribute to back strain. The first thoracic vertebrae should be centered over the sacrum, and the posterior superior iliac spines (PSIS) should be equal in height.
The sacroiliac (SI) joint is assessed by placing one thumb on the PSIS and the other on the spine of the sacrum. After asking the patient to raise the ipsilateral leg off the ground, determine if the PSIS moves down (normal) or up (SI joint pathology). In addition to assessing the SI joint, raising one leg while extending the back will exacerbate back pain in patients with facet joint disease or spondylolisthesis. If the patient prefers to stand leaned over slightly to one side with the hip and knee flexed, this suggests sciatic nerve irritation, most commonly from a herniated disk.
Range of motion in flexion and extension does not reliably distinguish among pathologic causes, but can provide a baseline to evaluate for therapeutic response. Normal range of motion of the back involves 40 to 60 degree of flexion. If the lumbar spine maintains its lordosis and flexion occurs at the hips when the patient bends forward, pathology of the lumbar spine, usually at the L4-5 or L5-S1 interspaces, should be suspected. Pain with flexion is consistent with sciatica, disk herniation, or lumbar strain. Normal extension of the lumbar spine is 20 to 35 degrees. Extension stresses the facet joints and narrows the foramina through which the nerve roots exit. Painful extension, therefore, is characteristic of facet joint pathology and arthritis.
Palpation of the spine is ideally performed in flexion. The spinous processes of the thoracolumbar spine are easily palpated except in extremely obese patients. Any lateral deviation of these processes suggests rotational deformity such as scoliosis or fracture. The distance between the spinous processes should be equivalent from one segment to the next. The supraspinous and interspinous ligaments are palpated in the recesses between the spinous processes (Fig. 7–9). Some helpful landmarks to remember include the iliac crests at the level of the L4 and L5 interspace and the S2 spinous process at the level of the PSIS (Fig. 7–10).
The supraspinous and interspinous ligaments are palpated between the spinous processes.
The L4-5 interspace is palpated between the iliac crests, while S2 is palpated at the level of the posterior superior iliac spines.
Pressure on the spinous processes is transmitted anteriorly to the arches and toward the vertebral bodies. For that reason, percussion of the spinous processes with a reflex hammer may aid in differentiating pain from the vertebral column versus deeper retroperitoneal structures. Generally, pain with percussion suggests spinal pathology such as a fracture or infection. Tenderness to percussion over the spine is 86% sensitive for bacterial infection, but is only 60% specific.9,14.
The facet joints are located approximately 3 cm lateral to the spinous processes in the thoracolumbar region. Like the cervical spine, the facet joints are both lateral to and between the spinous processes. Direct palpation of the facet joints is not possible in the thoracolumbar spine because they are deep to the paraspinous muscles.
Lastly, while the patient is still standing, have the patient stand on their heels to test the motor function of the L5 root and stand on tip toes to test the S1 root.
Once the patient is lying supine, perform a straight-leg raise test and crossed straight-leg raise test. With the knee extended, the leg is raised gradually. Pain before 30 degree of elevation is not consistent with nerve root irritation because only the dura is being stretched until this point. Elevation from 30 to 60 degree stretches the nerve root and reproduces pain due to a herniated disk (Lasègue’s sign). For either test to be considered positive, the pain must radiate beyond the knee. A positive straight-leg test is sensitive, but not specific, for herniated disc. The crossed straight-leg test is less sensitive for herniated disks, but 90% specific.15 An increase of pain with the Valsalva maneuver is also sensitive for sciatic nerve irritation.
The FABER (flexion, abduction, and external rotation of the hip) test for pathology of the hip and SI joints is also performed in the supine patient. The foot of the affected side is placed on the opposite knee. Pain in the groin suggests pathology of the hip, not the spine. Gentle, but firm, downward pressure on the flexed knee and opposite anterior superior iliac crest produces SI joint pain in patients with pathology there.
The majority of the neurologic assessment can be performed while the patient is lying supine. The neurologic examination should include an assessment of motor strength, sensation, and reflex testing. The location of cord injury can be determined by knowing how-to-test function at that level. In the lumbar spine, the L3, L4, L5, and S1 nerve roots are tested (Table 7–5 and Figs. 7–11 to 7–13). L5 motor nerve root testing evaluates strength of ankle and great toe dorsiflexion. L5 sensory nerve root damage would result in numbness in the medial foot and the web space between the first and second toe. The S1 nerve root is tested by evaluating ankle reflexes and sensation at the posterior calf and lateral foot. S1 radiculopathy may cause weakness of plantar flexion.15 The ability to squeeze the buttocks together (i.e., gluteus maximus) is an additional reliable motor finding of the S1 nerve root.
TABLE 7-5Physical Examination to test the Lumbosacral Nerve Roots ||Download (.pdf) TABLE 7-5 Physical Examination to test the Lumbosacral Nerve Roots
| ||L3 ||L4 ||L5 ||S1 |
|Sensory ||Anterior and medial thigh ||Medial foot ||Web space of 1st and 2nd digit ||Lateral foot |
|Motor ||Hip flexion ||Knee extension ||Big toe and ankle dorsiflexion ||Ankle plantar flexion |
Neurologic assessment of the L4 nerve root.
Neurologic assessment of the L5 nerve root.
Neurologic assessment of the S1 nerve root.
One neurologic test that is frequently overlooked, but often diagnostic, is vibratory sensation. A tuning fork is placed over a bony prominence supplied by the nerve root (e.g., medial malleolus for L4, patella for L3). The vibration will elicit discomfort that radiates upward to the back in the sensory distribution of the irritated nerve root. Vibratory sense is the most superficial layer of the nerve and thus is the most sensitive when there is early compression.
When attempting to determine the location of neurologic injury, several general principles are useful. Unilateral weakness suggests a radiculopathy, whereas bilateral weakness or spasticity is characteristic of a lesion within the spinal cord (i.e., myelopathy). Cauda equina syndrome should be suspected in patients with lower motor neuron findings, bilateral leg weakness, loss of rectal tone, saddle anesthesia, and urinary retention. Sensory deficits within a single dermatome support a radicular source of pain, whereas involvement of multiple dermatomes is more likely to be due to pathology within the cord (Fig. 7–14).
Dermatome distribution of spinal nerves.
Test the S1 nerve root by noting the function of the gluteus maximus muscle. Ask the patient to clench the buttocks together. If one side is weaker, there is likely a deficit of the S1 nerve root.
Perform the femoral stretch test by extending the hip in the prone position. This maneuver produces pain lateral to the midline in patients with facet joint pathology. Pain produced in the anterior thigh, however, suggests irritation of the L2-3 nerve roots.
Next, palpate the area of the sciatic nerve as it courses between the ischial tuberosity and the greater trochanter. If this produces tenderness, irritation of the nerve in this location should be suspected as opposed to irritation in the back. Piriformis syndrome is a cause of sciatic nerve irritation in this position and is covered in further detail in Chapter 17 “Pelvis.”
A sheet placed under the umbilicus in the prone patient will flex the lumbar spine and make the facet joints more apparent. The spinous processes should be equidistant. A step-off between L5-S1 and L4-L5 suggests spondylolisthesis. As in the standing patient, tenderness 3 cm lateral to the spinous process suggests facet joint pathology.