Anatomy

Seven cervical vertebrae make up the bony elements of the cervical spine. A typical cervical vertebra is similar to other vertebrae in that it is composed of a body and a neural arch (Fig. 3-1). The neural arch is composed of two pedicles that form the sides and two laminae that meet in the midline to form the roof. Projecting dorsally where the laminae meet is the spinous process, and projecting laterally from the junction of the pedicle and lamina is a transverse process on each side. Two articular processes, the superior and inferior, project upward and downward, respectively, from the junction of the pedicle and laminae on each side and articulate with similar processes on adjacent vertebrae to form the zygapophyseal or facet joints.

FIG. 3-1 A typical cervical vertebra: S, Spinous process; L, lamina; A, articular facet; P, pedicle; T, transverse process; B, body.

The first two cervical vertebrae are atypical in that C1, the atlas, has no body (Fig. 3-2). Its body is attached to C2, the axis, and forms the dens, or odontoid process. This arrangement allows for most of the rotation in the cervical spine. Strong ligaments bind C1 to C2, the most important of which is the transverse ligament. The seventh cervical vertebra, vertebra prominens, is also somewhat atypical in that it has a long spinous process that is easily palpable beneath the skin. (Patients sometimes misinterpret this bony prominence and its overlying soft tissue as a “mass.”)

FIG. 3-2 A, The axis. B, The atlas and transverse ligament (T). C, The articulation of the atlas and the axis.

Several major ligaments stabilize the cervical spine (Fig. 3-3). The anterior and posterior longitudinal ligaments are applied to the respective surfaces of the vertebral bodies. The posterior longitudinal ligament tends to be somewhat weak laterally where it crosses the disc, thus forming a point where disc herniation may occur. Some gliding motion is allowed to occur between vertebrae by relatively weak capsular ligaments that bind together each articular joint. The ligamentum flavum, or yellow ligament, is situated between adjacent laminae, and in the cervical spine, extremely strong ligaments—the nuchal ligament and interspinous ligaments—provide posterior support.

FIG. 3-3 Ligaments of the cervical spine: anterior longitudinal ligament (A); posterior longitudinal ligament (P); nuchal ligament (N); interspinous ligament (I).

The vertebrae are separated from each other by the intervertebral discs, which constitute approximately one fourth of the length of the vertebral column. Each disc is composed of an inner nucleus pulposus, which is mainly gelatinous, and an outer layer, the anulus fibrosus, which is mainly fibrous. The discs distribute stress over a wide area of the vertebrae, absorb shock, and allow mobility. The nucleus pulposus has a very high water content in early life, but with age this tends to diminish. With this loss of water, abnormal pressures begin to be exerted on the anulus, which may lead to herniation and/or disc degeneration. Pathologic changes in adjacent structures (facet joint arthritis or osteophyte formation) may eventually develop as well.

Eight pairs of nerve roots arise from the cervical spinal cord. Each nerve exits above the vertebra of the same number. Thus, the sixth nerve root exits at the C5–C6 disc space. Each nerve, except the first two pairs, leaves the spinal column by passing through an intervertebral foramen (Fig. 3-4). Each foramen has as its superior and inferior boundaries the pedicles of the adjacent vertebrae. Posterolaterally, it is bounded by the apophyseal joint and, anteromedially, by the so-called joint of Luschka. In the cervical spine, this foramen is quite small and is almost entirely occupied by the nerve root. Thus, anything that compromises this space, such as disc degeneration with spur formation, could cause pressure on the nerve root.

FIG. 3-4 The intervertebral foramen. Note the proximity of the joint of Luschka (L). The nerve root exits this foramen. Compression of the root may occur with disc herniation or from degeneration with collapse of the disc, narrowing of the foramen combined with ingrowth of osteophytes from the facet joint and disc.

Examination

Examination of the neck begins with observation of the posture of the head and neck in relation to the torso. Any decrease in the normal cervical lordosis is noted. The neck is gently palpated for tender areas and trigger points. The range of motion of the cervical spine is then measured, and any movement that reproduces pain is noted. Flexion, extension, right and left bending, and right and left rotation are all recorded. A complete neurologic examination, including muscle strength testing, is always performed. The peripheral nerves are percussed for tenderness and tested for function. In addition, the shoulders and elbows are always carefully examined, particularly if there is any radiation of the pain or numbness and tingling.

Roentgenographic Anatomy

The examination of all neck disorders should include a standard roentgenographic evaluation. The roentgenographic features of the cervical spine are well visualized by the following: (1) anteroposterior view (Fig. 3-5); (2) lateral views in flexion and extension; (3) oblique views in both directions to visualize the intervertebral foramen (Fig. 3-6); and (4) an open-mouth odontoid view to visualize the odontoid process and the relationship between C1 and C2.

FIG. 3-5 Anteroposterior (A) and lateral (B) views of the cervical spine. S, Spinous process; T, transverse process; B, body; A, articular (zygapophyseal) facet joint; P, pedicle; L, lamina. Note the slight lordosis and even spacing of the vertebrae and discs.

FIG. 3-6 Oblique view. S, Spinous process; F, intervertebral foramen; J, joint of Luschka; L, lamina; P, pedicle; A, articular facet joint; B, body.

Cervical Disc Syndromes

Disease of the cervical spine as a result of disorders of the disc will affect 50% of the population at some time, usually patients between the ages of 30 and 60. More than 90% of disc lesions in the cervical spine occur at the C5 and C6 levels, those being the most mobile segments. As disc degeneration occurs, two types of lesions result that produce very similar symptoms. The first of these is the soft disc protrusion or nuclear herniation. With this lesion, most common in the younger patient, a mass of nucleus pulposus begins to bulge outward, usually posterolaterally, at the area of the greatest weakness in the anulus fibrosus (Fig. 3-7). With severe disc protrusion, compression of the nerve root may occur, resulting in arm symptoms and radicular pain. Less severe herniation may produce only referred or axial spine pain, usually one-sided.

FIG. 3-7 Disc herniation (arrow) causing nerve root compression. Spur formation may occur in the same area.

The second, more common lesion results from chronic disc degeneration with subsequent settling or narrowing of the disc space and alterations in the surrounding structures including the facet joints. This is the so-called hard disc lesion, or cervical “spondylosis,” and occurs primarily in older age groups. As narrowing and collapse of the disc proceed, the vertebrae become more closely approximated, which leads to spur formation along the disc edges and at the joints of Luschka. Mild subluxation of the facet joints may also occur. All of these changes decrease the size of the intervertebral foramen, which may result in pressure on the nerve root. Inflammation and swelling may develop in conjunction with osteophyte formation, which further contributes to the narrowing of the foramen and nerve root compression.

Rarely, large posterior osteophytes along with degenerative narrowing of the bony canal may cause pressure on the spinal cord and produce mixed symptoms of upper extremity nerve root pain and lower extremity weakness. This is commonly termed cervical spondylosis with myelopathy. It is the most common cause of spastic paraparesis in the adult. In many of these cases, the lower extremity symptoms are much more disabling than the neck symptoms, a situation that can cause some initial confusion in determining their etiology.

CLINICAL FEATURES

Disc disease can produce several overlapping syndromes in the cervical spine: (1) axial or referred spine pain, (2) radicular arm symptoms from nerve root compression and, rarely, (3) cord compression symptoms.

Pain associated with disc disease usually develops gradually. Degeneration or slow herniation may initially cause only neck and referred pain, which often begins in the interscapular area and may be mistaken for a shoulder disorder. It is almost always unilateral. Patients may complain of a tightness or stiffness in the neck that worsens with activity. Morning stiffness is common, and certain movements, especially extension, exacerbate the pain. Looking backward over the shoulder of the affected side may also intensify the pain. In rare cases, pain in the anterior aspect of the chest (“cervical angina”) or breast may be the presenting complaint. Coughing, sneezing, and straining can accentuate the pain. If nerve root irritation or compression develops, pain may radiate into the shoulder and arm and along the radial aspect of the forearm (Fig. 3-8). Numbness and tingling are often noted in these same areas, and referred pain, which does not follow a dermatome pattern, is common along the upper medial border of the scapula. Headaches are not uncommon, and dysphagia has even been reported secondary to large anterior osteophytes. Headache or jaw pain may be present with high disc lesions. Patients with radicular pain sometimes find relief of the nerve root tension by abducting their arm and resting the forearm on the top of the head.

FIG. 3-8 Volar and dorsal dermatome pattern of the forearm and hand. Pain and paresthesias may radiate into these areas when the affected nerve root is compressed. NOTE: Extremity symptoms caused by disc disease are almost always unilateral.

Examination frequently reveals a decreased range of motion. Pain on hyperextension and local tenderness in the cervical spine are often observed. Trigger point tenderness is commonly noted in the area of referred pain in the interscapular region. (This pain is often reproduced by specific neck movements, usually extension with rotation to the involved side.) Pressure against the top of the head also may reproduce the pain in the arm (Fig. 3-9). Some sensory changes are occasionally present along the specific dermatome, but the sensory examination is frequently not very helpful. Motor weakness and reflex changes may be noted (Table 3-1).

FIG. 3-9 Vertex compression test. Pressure downward on the head with extension and tilting the head to the affected side may narrow the neural foramen and reproduce neck and/or arm pain when disc herniation or spondylosis is present.

Table 3-1 Clinical Features of Common Cervical Disc Syndromes

Spondylosis in the cervical spine may occasionally produce symptoms referable to the lower extremities (cervical spondylotic myelopathy). These symptoms occur as a result of pressure of posterior osteophytes on the anterior portion of the cervical spinal cord. The symptom complex may appear as a combination of cervical root and cord symptoms, but commonly, cord symptoms predominate. The patient may have a typical disc syndrome in the upper extremities, but in addition, gait difficulties, weakness, and spasticity may be present in the lower extremities. The lower extremity symptoms have a gradual onset at about 50 years of age and progress slowly. They are often more disabling than the neck symptoms, which are usually mild. The leg weakness is most severe in the proximal muscles. Bowel and bladder changes are rare. (Many patients with myelopathy may not appreciate their weakness because the changes in gait and balance are subtle.) Physical findings are those of an upper motor neuron lesion with hyperreflexia, clonus, and pathologic reflexes.

SPECIAL STUDIES

In most cases, the diagnosis is clear without further testing. Neck, interscapular, and/or arm pain that is aggravated by neck motion is typical. Eventually, however, the following studies may be needed:

1 Plain roentgenograms are usually performed first. Anteroposterior and lateral views are sufficient. They are usually normal in soft disc rupture. With chronic degenerative disc disease, however, there is loss of the height of the disc space with anterior and posterior osteophyte formation. Encroachment on the intervertebral foramen by osteophytes is noted on oblique films (Fig. 3-10).

2 Myelography, sometimes followed by computed tomography (CT), remains useful in the evaluation of cervical radiculopathy, although with the development of magnetic resonance imaging (MRI), it is less commonly used. It is helpful in localizing the lesion but is not without some morbidity and is indicated only under two circumstances: (1) if surgical intervention is contemplated, or (2) if other serious spinal abnormality is suspected. Loss of the normal root “sleeve” and indentation of the dural sac are often seen (Fig. 3-11). Spinal fluid analysis performed at the time of myelography may show a slight increase in protein content.

3 MRI is also valuable in the assessment of the cervical spine and is more commonly used than myelography. It is attractive partly because it is noninvasive and uses no ionizing radiation. It should be used selectively because of its continuing high cost. Many patients are excluded from this modality for various reasons: obesity, the presence of pacemakers, internal fixation devices, and claustrophobia, among others (although newer “open” models cause less claustrophobia). The examination time is also quite lengthy. Indications for its use are generally the same as those for myelography. Like myelography, magnetic resonance imaging is usually indicated later in the disorder, after several weeks have passed without recovery. CT scanning, although less expensive, is not as helpful in evaluating degenerative disc disease in the cervical spine as it is in the assessment of traumatic conditions of the neck.

4 Electromyography can confirm the diagnosis in some cases if the disorder has caused nerve root compression long enough. It can also differentiate neurologic from muscular conditions. Nerve conduction studies help rule out peripheral nerve disorders.

5 Discography is controversial. It is also occasionally performed in the evaluation of cervical disc disease, but the diagnosis can usually be well established on the basis of the history, physical examination, and plain films alone.

6 Thermography is mentioned only for completeness. Its validity is uncertain, and it is not commonly used.

FIG. 3-10 Lateral (A) and oblique (B) roentgenograms showing degenerative disc disease at the C5–C6 level. Note the osteophyte formation and narrowing of the intervertebral foramen (arrow). Compare with the foramina above and below.

FIG. 3-11 Myelographic findings in cervical disc disease. Note the filling defects from osteophyte formation on the lateral view (A) and absence of the normal root sleeve (arrows) on the AP view (B).

NOTE: Roentgenographic studies are not always conclusive. False-negative and false-positive results are fairly common. These studies should be performed only as an adjunct to, not instead of, a good history and clinical examination. When the results are uncertain, it is best to reexamine the patient. If the symptoms do not correlate well with the roentgenographic findings, it is best to continue to treat the symptoms and not the roentgenogram. Remember that “abnormal” roentgenographic findings in the spine are present in up to 35% of asymptomatic adults.

TREATMENT

Cervical disc disorders are always first treated conservatively unless a major neurologic deficit is present.

1 Rest is the cornerstone of therapy for cervical disc disease. In acute disc protusion, it permits the healing of soft parts to occur. (What happens to the disc material is unknown. One theory is that the extruded disc material may act as a foreign body and become absorbed or transformed into scar tissue.) In chronic disc disease, rest allows the inflammatory reaction to subside. A short period of bed rest may be beneficial but is rarely practical. Various soft collars that restrict motion and give support may be helpful (Fig. 3-12).

2 Physical therapy is often prescribed, but its usefulness is uncertain. Moist heat applied to the affected area will help relieve tenderness and muscle pain temporarily. Massage may provide temporary relief of the trigger point soft tissue pain. Home cervical traction may also help (Fig. 3-13), although it is improbable that the neck can actually be “stretched.” (Although most forms of physical therapy are of an unproven value, some patients do seem to respond. Pain relief, however, seems short-lived, and any overall improvement usually parallels what would have probably occurred naturally.)

3 Nonsteroidal anti-inflammatory drugs (NSAIDs) may be helpful, especially for degenerative disc disease. Their analgesic effect may not be sufficient to relieve pain when nerve compression is present, however, and narcotics may be required.

Muscle “relaxers” are not effective except as sedatives (see Chapter 18). Neck pain is not caused by muscle tissue, nor can “spasm” ever be truly demonstrated. These medications probably are only effective via their tranquilizing effect. They may be helpful when given at night to allow the patient to rest, but many patients are bothered by their sedative side effects during the day.

4 Epidural pain blocks are often valuable when radicular pain is present.

5 After the acute pain subsides, a program of gentle, graded isometric exercises is recommended (Fig. 3-14). Recurrences are prevented by avoiding fatigue and poor postural habits, especially hyperextension and other extremes of neck position (Fig. 3-15). A pillow approximately 7.5 to 10 cm thick should be used for sleeping and should be placed under the neck rather than under the head. An overly thick pillow may place the head in too much flexion, whereas a thin one may allow too much extension to occur. Most patients may continue a reasonable daily work schedule unless the pain is particularly intense (Fig. 3-16).

FIG. 3-12 Proper usage of the cervical collar. A, A collar too high places the neck in too much extension. B, A collar too short does not immobilize and allows too much flexion. C, Proper height of the collar maintains the head in a slightly flexed or neutral position.

FIG. 3-13 Proper usage of cervical traction. The direction of pull should be neutral; 4 to 6 lb of weight should be used for 20 to 30 minutes. It should be repeated three to four times daily, depending on the response. The pressure should be equally distributed between the chin and the occiput.

FIG. 3-14 Isometric neck exercises. A, The hand is placed against the side of the head slightly above the ear, and pressure is gradually increased while resisting with the neck muscles and keeping the head in the same position. The position is held 5 seconds, relaxed, and repeated five times. The exercise is performed on the other side and then from the back and front (B and C). The exercise should be performed three to four times daily.

FIG. 3-15 The hyperextended “spectator” attitude that often causes neck strain and aggravates disc disease. The head and neck should be maintained in a neutral position at all times. Positions that produce sharp angulation or rotation of the head, such as sleeping on the abdomen or resting on a couch with the armrest as a “pillow,” should also be avoided.

Fig. 3-16 Algorithm for suspected cervical disc syndrome.

PROGNOSIS

Most patients will improve with time, and fewer than 5% will require surgery. Patience is important. The period required for improvement varies considerably among patients. Several weeks may be needed before full recovery occurs. Patients may be advised, however, that unless a major neurologic deficit is present, there is generally no danger in waiting and continuing conservative treatment. Recurrences occur occasionally and are treated in the same manner. Surgery is reserved for those patients in whom the pain and level of disability become intolerable or in whom a major neurologic deficit has developed. It is indicated for relief of radicular arm pain, but it is not helpful for axial neck pain. The procedure consists of removal of the affected disc, usually followed by arthrodesis of the two adjacent vertebrae with a bone graft (Fig. 3-17). Some soft disc protrusions are occasionally removed without fusion. The arm pain usually subsides immediately after surgery, and osteophytes that have formed in the foramen and adjacent structures are usually absorbed within 9 to 18 months.

FIG. 3-17 Arthrodesis of the cervical spine. The disc is removed and replaced with a bone graft.

The treatment of myelopathy is usually nonoperative if symptoms are mild. Unfortunately, many patients who develop weakness in the legs find that the paralysis slowly progresses over time. Surgery is warranted in these more severe cases, but the decision to operate is difficult because the operative management of these patients is complicated and the results are often unrewarding.

NOTE: Cervical spondylosis can predispose the patient to acute spinal cord injury, often in the elderly and commonly from injuries that cause hyperextension. A central cord syndrome may even result.

Cervical Sprain

Most soft tissue injuries of the cervical spine are the result of a hyperextension force. Although a variety of injuries can produce a cervical sprain, the condition has become virtually synonymous with the disorder that develops in rear-end automobile collisions called “whiplash.”

Rarely is there any osseous damage. Most of the force is probably absorbed by ligaments, muscles, and discs, but the specific source of symptoms is often never found. Acute disc protrusion is not common, but disc “injury” may occur on occasion, and serial roentgenograms taken at later dates may show significant progressive degenerative changes. Any soft structures, including muscle, anterior longitudinal ligament, esophagus, and trachea, may be stretched. Dysphagia and hoarseness are sometimes seen shortly after the injury. Hemorrhage and edema may be present in the prevertebral area, and the sympathetic nerve chains, which are located near the vertebral bodies, are occasionally stretched. This may produce somewhat unusual symptoms, such as nausea, tinnitus, blurred vision, and dizziness.

Chronic pain that continues for weeks or months is not uncommon. On rare occasions, degenerative changes may develop from the injury at one or more levels in a previously normal cervical spine, and this may lead to prolonged disability. Similarly, patients with previously asymptomatic degenerative disc disease may develop their first symptoms of a cervical disc syndrome after a hyperextension injury.

SPECIAL STUDIES

After the initial examination, if there is any reason to suspect a significant cervical spine injury, a full lateral roentgenogram of the cervical spine should be taken without moving the patient. This view should always include the body of the seventh cervical vertebra; if it does not, the vertebra is probably being obscured by the shoulder soft tissue shadow. In this case, the shoulders should be pulled down manually and the roentgenogram repeated. If a satisfactory view of C7 still has not been obtained, then a “swimmer’s” view may be performed. If no significant injury is seen on this view, then the remainder of the cervical spine films are obtained. Usually, results of the initial roentgenographic examination are normal, but with the passage of time, reversal of the normal cervical lordosis may rarely be observed (Fig. 3-18). This finding is often seen in patients with prolonged disability. Late degenerative changes may even occur. “Loss of the normal cervical lordosis,” often quoted on early roentgenograms, is probably not significant. Any degenerative changes present in the cervical spine at the time of the initial injury should also be noted for both medical and medicolegal purposes. Further roentgenographic studies are usually not indicated. CT and bone scanning may be helpful to rule out fracture, however. MRI is usually not helpful and is generally not indicated.

FIG. 3-18 Lateral roentgenogram showing reversal of the cervical lordosis. This abnormal curvature can occasionally become permanent in whiplash injury.

TREATMENT

1 A short period of rest is important in the treatment of the acute cervical strain, although the ideal treatment program is controversial. A soft protective collar holding the neck in slight flexion may be useful. Early activity is encouraged, however, and excessive passive care should be avoided.

2 Analgesics are given in amounts sufficient to relieve any acute pain. Anti-inflammatory drugs given soon after the injury may be helpful, especially in the patient who has preexisting degenerative disc disease.

3 Cold should be used initially. Heat should be avoided early after the injury because it may further increase swelling. It may be helpful later in the course of care.

4 When the acute pain begins to subside, isometric and gentle range-of-motion exercises are started, and wearing of the collar is gradually discontinued. The patient is encouraged to return to normal activities as soon as possible. If symptoms persist after 4 to 6 weeks, formal physical therapy may be beneficial (Fig. 3-19).

FIG. 3-19 Algorithm for cervical strain.

Disc Calcification

Calcification of the intervertebral disc is not uncommon. It frequently occurs in the dorsal spine of adults in the anulus fibrosus and is probably secondary to a degenerative process. Multiple disc calcifications also occur with ochronosis and other rare metabolic disorders. Disc calcification is usually an incidental roentgenographic finding and generally does not produce symptoms, especially in adults.

On rare occasions, discs may also calcify in children, but in these cases, it is usually the cervical spine that is involved. In this age group, the condition may also cause a definite clinical entity with symptoms, sometimes called “calcific discitis” or acute disc calcification. The etiology is unknown, but it may represent a nonspecific inflammatory reaction. It is probably not infectious in nature. In contrast to the adult, it is the nucleus pulposus that calcifies in the child.

CLINICAL FEATURES

Disc calcification has its onset at about the age of 7 years and usually begins with neck pain and stiffness. Localized tenderness and a decrease in the range of motion of the cervical spine are usually present. A mild torticollis may be noted. There is usually an elevation of the temperature, sedimentation rate, and white blood cell (WBC) count.

Roentgenograms reveal the disease to primarily affect the lower discs in the cervical spine (Fig. 3-20). Usually, a single disc is involved, but multiple discs may be affected. The calcification usually begins to regress with the onset of symptoms.

FIG. 3-20 Disc space calcification (arrow).

Torticollis

Torticollis, sometimes called “wryneck,” is contraction or contracture of the muscles of the neck that occurs and causes the head to be tilted to one side. It is commonly accompanied by rotation of the chin to the opposite side with flexion. It is usually a symptom of some underlying disorder. The term is often used incorrectly in cases when the torticollis may simply be positional. The condition has been attributed to more than 50 causes. It may be acquired as a result of trauma or disease, but more than 80% of cases are congenital in nature.

CONGENITAL MUSCULAR TORTICOLLIS

This deformity is usually noted at birth and is much more common after breech deliveries. It results from a unilateral contracture of the sternocleidomastoid muscle. The cause is unknown, but fibrosis of the muscle occurs, possibly secondary to a vascular disturbance in the muscle. A “tumor” consisting of dense fibrous tissue is often found in the muscle shortly after birth. This mass gradually subsides over the ensuing weeks to leave a shortened and contracted sternocleidomastoid muscle. If untreated, secondary changes appear in the cervical vertebrae, and marked asymmetry of the face becomes apparent. These changes frequently persist despite later treatment. Congenital muscular torticollis is often associated with other disorders such as hip dysplasia and clubfoot.

CLINICAL FEATURES

The diagnosis of congenital muscular torticollis generally can be made shortly after birth. The “mass” is usually palpable, and the head is characteristically tilted toward the side of the mass and rotated in the opposite direction (Fig. 3-21). Roentgenograms of the cervical spine are usually performed to rule out injury and congenital osseous disorders of the cervical spine.

FIG. 3-21 Congenital muscular torticollis.

TREATMENT

Conservative treatment, if instituted early, usually results in a cure. No improvement can be expected without treatment. In mild deformities, gentle stretching exercises carried out by the mother usually correct the problem. The aim is for full range of motion. The exercises should be repeated several times daily. The crib should be placed so that the child must turn toward the corrected position when someone enters the room. Most cases improve within 6 months. The mass usually resolves by this time as well. Persistent torticollis may result in facial asymmetry and skull deformity (plagiocephaly).

Surgery is reserved for late cases or those who fail to respond to conservative treatment. The procedure consists of the release of the sternocleidomastoid muscle followed by traction or casting and exercises. The results are usually good.