PART 2 in Microsoft Office

Maker QR Code JIS X 0510 in Microsoft Office PART 2

Intervertebral Disc (Annulus Fibrosus)

Figure 11-2 The main ligamentous structures of the spine A Buckling of the yellow ligament (ligamentum avum) may compress the nerve root or the spinal nerve at its origin in the intervertebral foramen, particularly if the foramen is narrowed by osteophytic overgrowth B Posterior aspect of the vertebral bodies Fibers of the posterior longitudinal ligament merge with the posteromedial portion of the annulus brosus, leaving the posterolateral portion of the annulus relatively unsupported (Reproduced by permission from Finneson)

circumscription to the territory of a root, and factors that excite it The mechanism is stretching, irritation, or compression of a spinal root within or central to the intervertebral foramen The pain is sharp, often intense, and usually superimposed on the dull ache of referred pain; it nearly always radiates from a paracentral position near the spine to some part of the lower limb Coughing, sneezing, and straining characteristically evoke this sharp radiating pain, although each of these actions may also jar or move the spine and enhance local pain; jugular vein compression, which raises intra-

spinal pressure and may cause a shift in position of the root, has a similar effect In fact, any maneuver that stretches the nerve root eg, straight-leg raising in cases of sciatica evokes radicular pain The patterns of radicular pain due to involvement of particular roots are described in the sections on prolapsed discs further on in the chapter, and the distribution of cutaneous innervation of the spinal roots is shown in Figs 9-2 and 9-3 The most common pattern is sciatica, pain that originates in the buttock and is projected along the posterior or posterolateral thigh It results from irritation of the L5 or S1 nerve root Paresthesias or super cial sensory loss, soreness of the skin, and tenderness in certain circumscribed regions along the nerve usually accompany radicular pain If the anterior roots are involved as well, there may be re ex loss, weakness, atrophy, and fascicular twitching In patients with severe circumferential constriction of the cauda equina due to spondylosis (lumbar stenosis), sensorimotor impairment and sometimes referred pain are elicited by standing and walking The neurologic symptoms involve the calves and the backs of the thighs, thereby simulating the exercise-induced symptoms due to vascular insuf ciency hence the term spinal claudication (see page 179) Of importance is the observation that referred pain from structures of the lower back (sometimes called pseudoradicular) does not, as a rule, project below the knees and is not accompanied by neurologic changes other than a vague numbness without demonstrable sensory impairment The subcutaneous tissues within the area of referred pain may be tender Of course, local, referred, and radicular pain may occur together Pain resulting from muscular spasm usually occurs in relation to local pain The spasm may be thought of as a nocifensive re ex for the protection of the diseased parts against injurious motion Muscle spasm is associated with many disorders of the low back and can distort normal posture Chronic muscular contraction may give rise to a dull, sometimes cramping ache One can feel the tautness of the sacrospinalis and gluteal muscles and demonstrate by palpation that the pain is localized to them However, except for the most severe degrees of spasm in acute injury of the back, the contribution of this component to back pain is relatively small Other pains, often of undetermined origin, are sometimes described by patients with chronic disease of the lower part of the back: drawing and pulling in the legs; cramping sensation (without involuntary muscle spasm); tearing, throbbing, or jabbing pains; and feelings of burning or coldness These sensations, like paresthesias and numbness, should suggest the possibility of nerve or root disease In addition to assessing the character and location of the pain, one should determine the factors that aggravate and relieve it, its constancy, and its relationship to activity and rest, posture, forward bending, and cough, sneeze, and strain Frequently, the most important lead comes from knowledge of the mode of onset and the circumstances that initiated the pain Inasmuch as many painful conditions of the back are the result of injuries incurred during work or in automobile accidents, the possibility of exaggeration or prolongation of pain for purposes of compensation must always be kept in mind