REIDER PART 244

304 Chapter 8_Cervical and Thoracic Spine

individuals. Thcsc muscles originate on the mastoid processes of thc skuli and insert on the sternum and the clavicle at the sternoclavicular joints, forming a prominent V configuration.

Sternum. Procceding distally, the examiner observes the sternal notch at the confluence of the two sternocleido-mastoid muscles. The notch is typically located at the level of the T3 and T4 vertebral bodies. Below this cxtends the sternum, a relatively narrow fiat bonę. Although it serves as the origin of the pectoralis major muscle, the sternums central strip has little overlying soft tissue. It is, therefore, usually visible as a depression between the breasts in women or the pectoralis major muscles in men. Deformities of the sternum do occur. These include pec-tus excavatum, an abnormally concave sternum, and pectus carinatum, an abnormally convex sternum. The finał significant anterior landmark (for orthopaedic purposes) is the umbilicus, which is contained in the T10 dermatome.

■ GAIT

An evaluation of gait is imperative for any thorough assessment of thc spine. Some of the neurologie syndromes associated with disorders of the cervical or thc thoracic spine produce characteristic gait disturbances. Obser-vation of the spine during ambulation can also provide yaluable information about the dynamie and the static behavior of the weightbearing cervical spine.

Shuffling and Slap Foot Gaits. Injury to the posterior columns of the spinał cord produces a posterior cord syn-drome, a condition characterized by the loss of proprio-ception in the extremities that are innervated below the lesion. When the individual with a posterior cord syn-drome takes a step, he or she is unaware of the position of the swinging foot in space and thus is unable to pre-dict the exact moment of heel strike. This uncertainty may be manifested by a shuffling gait, in which the feet are dragged on the ground during thc swing phase, or a slap foot gait, in which the feet strike the ground in a violent, unpredictable manner. Although a shuffling gait is typical of posterior cord syndrome, it may also be seen in a variety of other neurologie disorders, such as Parkinson’s disease.

Broad-Based Gait. A broad-based or halting gait may

be seen when stenosis of the cemcal spine is complicated by compression of the spinał cord. In this gait pattem, which is caused by faulty programming of the sequence of muscle movements necessary for a normal gait, the patient s stance is widened owing to balancing difficulties during single leg stance. The rhythm of the gait is fre-ąuently jerky, again owing to central programming dys-function. The pathogenesis of this pattern is unclear, but these patients freąuently have difficulty walking over uneven ground and complain of loss of balance.

Rangę of Motion

Cervical Spine

To properly assess the rangę of motion of the cervical spine, it is important that the thoracic spine be sup-ported. This is accomplished most easily by having the patient sit in a straight-backed chair. Ideally, the chair back should extend to the midscapular level but not above it (Fig. 8-10). In assessing cach direction of move-ment, the examiner tries not only to measure the amount of motion possible but also to determine whether or not

Figurę 8-10. Neutral position for evaluation of flexion and extcnsion. A, Cemcal. B, Thoracic.