Chapter 4: The Vertebral Column

36. Describe age-related changes in the spinal column.

(1) Osteophytes tend to form at the end plates, beginning in the third decade. These are found most commonly at the apices of the curves, which are areas of greatest stress (C4 to C5, T9 to T10, and L3 to L4). Osteolytic changes at the end plates may be seen around age 50, with patches most common in the cervical region. Where there is weakness of the end plate, the disc tissue may protrude through into the trabecular bone of the body (Schmorl's nodes). (2) The discs gradually lose water content with age, resulting in a diminished length to the spinal column and, in all likelihood, diminished ability to absorb compressive stress, which is passed increasingly on to the vertebral body below. The collagen content also shifts with an increased concentration of type II collagen at the anterior annulus. The reduction in disc height may also increase the likelihood of entrapment of the exiting peripheral nerves at the intervertebral foramen, because the decreased disc height will narrow the foramen. (3) The density of the cancellous bone of the body decreases with age, resulting in an increasing load on the cortical bone. The effect is to decrease stiffness, resulting in greater creep and slower recovery of tissues. This increases the likelihood of overuse injury, including compression fractures of the bodies.

27. Identify the ligaments that are unique to each of the areas, including the motions each ligament checks.

(a) Thoracic region—The supraspinous ligament runs from C7 to the sacrum but blends with the insertion of the lumbar extensors. Therefore, although not really unique to the thoracic region, it is not obvious in the lumbar region and changes its name in the cervical region. The supraspinous ligament checks flexion. (b) Lumbar region—The interspinous and intertransverse ligaments are well developed in the lumbar area only. The interspinous checks flexion, while the intertransverse ligaments are important checks to lateral flexion to the opposite side as well as to rotation in both directions. (c) Cervical region—The alar ligaments are unique to the segments between C2 and the occiput. They are paired ligaments attached to the dens and to the foramen magnum. The alar ligaments check rotation between C1 and C2. The supraspinous ligament changes to the ligamentum nuchae, which runs from C7 to the occiput of the skull. It predominantly checks flexion.

6. Which of the following accurately describes what happens to the intervertebral foramen during extension? A. Intervertebral foramen becomes smaller. B. Intervertebral foramen remains the same size. C. Intervertebral foramen becomes larger. D. Intervertebral foramen becomes square in shape.

A Rationale: During extension of the spine, the intervertebral foramen is narrowed, and the spinous processes move closer together.

18. Which of the following statements best fits the description of the sacroiliac ligaments? A. The sacroiliac ligaments are reinforced by fibrous expansions from the erector spinae and gluteus maximus. B. The fascial support is greater anteriorly than posteriorly. C. The sacrotuberous and sacrospinous ligaments are not part of the sacroiliac ligaments. D. The short posterior sacroiliac ligament is considered by some just a capsular reinforcement.

A Rationale: The sacroiliac ligaments include all of the named sacroiliac ligaments and the sacrotuberous and sacrospinous ligaments. The system is well reinforced posteriorly by fascia and by several fibrous expansions from posterior muscles (including the gluteus maximus and erector spinae). The anterior sacroiliac ligament is considered by some to be a capsular ligament, and the interosseous sacroiliac ligament (including its short posterior portion) is considered the most important ligament of the complex.

12. Which of the following muscles flexes the mid/lower cervical spine and extends the upper cervical spine? A. Sternocleidomastoid muscles B. Anterior scalene muscles C. Rectus capitus muscles D. Oblique capitus muscles

A Rationale: The sternocleidomastoid (SCM) muscle has a unique function as it produces cervical flexion and suboccipital extension at the Atlanto-Occipital (AO) joint. It also can produce rotation to the same side when contracted unilaterally

22. Which of the following factors is the primary contributor to the vertebral body's decreased ability to withstand compressive forces as it ages? A. Loss of horizontal trabeculae B. Loss of vertical trabeculae C. Loss of osteophyte formation D. Loss of cortical bone

A Rationale: The vertical trabeculae help the vertebral body to withstand shear force, and the horizontal trabeculae are primarily responsible in supporting compressive forces.

34. What effect will normal gravitational moments tend to have on a weak sacroiliac joint?

Although ordinarily the sacroiliac joint ligaments are adequate to their task of preventing rotation between the ilia and the sacrum, excessive forces across one or both of the sacroiliac joints or weakening of the ligaments can lead to temporary or permanent ligamentous plasticity. For example, if the ligaments fail to prevent it, the ilium may actually rotate posteriorly with respect to the sacrum (a movement caused by the normal forces acting around the joint). This creates distortion at the pubic symphysis as well, with the pubis on the side of the posteriorly torsioned ilium sitting high with respect to the adjacent pubis.

21. Which of the following accurately describes what happens to the articular surface of the facet joints of the mid/lower cervical spine during cervical extension? A. Distraction of articular surfaces B. Compression of articular surfaces C. No change at the articular surfaces

B

8. In the cervical spine, the greatest amount of rotation is available at which of the following motion segments? A. C0 to C1 B. C1 to C2 C. C4 to C5 D. C6 to C7

B Rationale: Approximately 55% to 58% of total rotation of the cervical spine occurs at the atlantoaxial joint (C1 to C2).

15. Which of the following most accurately describes the motion segment anatomical structures that will limit anterior translation of L5 on S1? A. Shape of the intervertebral disc and the anterior annular fibers of the intervertebral disc B. The iliolumbar ligament and posterior annular fibers of the intervertebral disc C. The anterior longitudinal ligament and iliolumbar ligament D. Posterior longitudinal ligament and intertransverse ligament

B Rationale: The angle created by the L5 on S1 segment is quite large and requires support from several structures. The iliolumbar ligament and posterior longitudinal ligament play a large role in stabilizing the fifth vertebrae on the sacrum. The intervertebral disc also helps to stabilize this joint through resistance of translation by its posterior fibers

1. Which of the following is true with regard to the structure of the annulus fibrosis of the normal intervertebral disc? A. Annular lamina are oriented 60° to the horizontal plane of the intervertebral disc. B. It resists tensile forces in all directions. C. The water and proteoglycans content of the annulus is greater than the collagen content. D. Annulus is vascular in the adult.

B Rationale: The lamellae in the annulus fibrosis are arranged in concentric rings that totally enclose the nucleus. The collagen fibers in adjacent rings are oriented in opposite directions at 120° to each other. This fiber arrangement would allow resistance to tensile forces in all directions.

11. The (R) alar ligament limits ____________________ of C1 on C2. A. (R) rotation B. (L) rotation C. Extension D. Both (R) and (L) lateral flexion

B Rationale: The two alar ligaments arise from the axis on either side of the dens and extend laterally and superiorly to attach to the medial sides of the occipital condyles. The left alar ligament will resist right rotation, and the right alar ligament resists left rotation.

9. The orientation of the uncinate processes in the cervical spine function to limit which of the following motions? A. Vertebral body anterior shear B. Vertebral body lateral translation C. Vertebral body superior translation D. Vertebral body posterior shear

B Rationale: The uncinate processes are seen along the lateral margins of the vertebral bodies from C3 to C7. These structures are the primary limiter of lateral translation of the cervical spine during motion.

23. Which muscle serves as an important frontal and horizontal plane stabilizer of the trunk? A. Longissimus thoracis B. Quadratus lumborum C. Rectus abdominus D. Iliocostalis lumborum

B The quadratus lumborum serves an important role in both frontal plane and horizontal plane stabilization by "fixing" the pelvis.

4. Which of the following may contribute to a dysfunction of trunk deviation (L) with forward bending? A. Tight erector spinae muscles (R) B. Stiff facet joint capsule on (L) C. Poor strength (L) internal and external oblique muscles D. Facet joint osteophyte on (R)

B A tight capsule on the (L) would draw the trunk to the side of the tightness. Tight muscles on the right would cause a (R) deviation. Inadequate anterior muscle strength would not be a factor as they are not active in this motion. An osteophyte on the (R) would cause limits to extension and not flexion

35. Describe how maintaining the head in normal vertical alignment (head/optical righting) causes the pelvis, spine, and joints of the lower extremities to behave as part of a closed kinematic chain.

Because, in most instances, the head is maintained in an upright position with a vertical orientation, the head is in essence fixed along a vertical axis. When one of the body segments in weight-bearing throws the head out of alignment, the adjacent body parts will do whatever is necessary to get the head aligned over the sacrum as closely as possible, because this minimizes bony stresses. If the head is aligned properly over the sacrum in both the sagittal and the frontal planes, the spine is considered to be neutral or compensated. For example, if the hips are being pulled into flexion by tightness in the iliopsoas (anterior pelvic tilt), the trunk does not remain forwardly flexed on the anteriorly tilted pelvis. Instead, compensation occurs by extending the lumbar spine. Similarly, if there is a short leg on the right, bilateral stance would tip the trunk and head to the right. Instead, the spine compensates by laterally flexing to the left, and if necessary, the cervical spine fine-tunes the positioning of the head vertically by laterally flexing to the right again.

14. The orientation of the facet joints in the thoracic spine causes the facets to function best in which of the following functions? A. Limiting lateral flexion B. Limiting rotation C. Limiting extension D. Limiting lateral translation

C Rationale: All motions are possible in the thoracic spine, but the ranges of flexion and extension are extremely limited by the rigidity of the rib cage and by the orientation of the facet joint in the frontal plane.

10. The physical therapy evaluation of a patient's cervical spine determines that compression of the (R) C5/C6 facet joint reproduces the patient's symptoms. Which of the following osteokinematic movements would be primarily responsible for reproducing the patient's symptoms? A. Flexion B. (R) rotation C. (L) rotation and (R) lateral flexion D. (R) rotation and (L) lateral flexion

C Rationale: Due to the coupled motion pattern seen in the spine, compression of the (R) facet would occur primarily with rotation to the (L) and with (R) lateral flexion. The compression occurs with (R) lateral flexion as a coupled rotation to the (L) would occur.

3. Which of the following structures would be best suited to resist the tensile forces produced during spinal extension? A. Posterior vertebral body B. Posterior longitudinal ligament C. Anterior longitudinal ligament D. Facet capsule

C Rationale: During extension of the spine, the posterior vertebral body and facet joint surfaces would have a compressive force placed on them. This compressive force would not affect the facet joint capsule. The posterior longitudinal ligament would become slack, and the anterior longitudinal ligament would be the only structure listed above to resist the tensile force being produced by an extension motion

7. Which of the following describes the lumbar spine facet joint arthrokinematic motion during (L) lateral flexion in the neutral position? A. Ipsilateral facet moves caudal and anterior; contralateral facet moves caudal and lateral. B. Ipsilateral facet moves cephalic and posterior; contralateral facet moves caudal and posterior. C. Ipsilateral facet moves caudal and anterior; contralateral facet moves cephalic and posterior. D. Ipsilateral facet moves cephalic and medial; contralateral facet moves cephalic and medial.

C Rationale: During lateral flexion to the left, the ipsilateral facet would travel in a caudal direction. Due to the coupled motion of the spine, there would also be slight rotation of the segment in the opposite direction; therefore, the ipsilateral facet would move slightly anterior. On the contralateral side, the facet would move in a general cephalic direction with a slight posterior rotation due to the coupled motion.

2. Which of the following describes biochemical changes that occur in the intervertebral disc with aging? A. Increased proteoglycan concentration in the nucleus pulposus B. Increased water-binding capacity C. Increased collagen content in nucleus pulposus D. Increased elastin content in the annulus fibrosis

C Rationale: During maturation and aging, there is a change in the type and amount of collagen content in the nucleus pulposus. The total amount of collagen increases steadily from about 6% to 25% of the dry weight of the center of the nucleus pulposus to 70% in the outer annulus.

5. Which of the following most accurately describes the primary tissue biomechanics that occur during lumbar rotation in a neutral position? A. Shear force on the vertebral body; ipsilateral facet compressed B. Compression on the vertebral body; ipsilateral joint capsule on slack C. Shear force on the vertebral body; ipsilateral joint capsule stretched D. Compression on the vertebral body; ipsilateral facet compressed

C Rationale: During rotation of the lumbar spine, a shear force would be applied to the vertebral body as translation occurs. At the facet surfaces, there would be a distractive force on the side to which the rotation occurred (ipsilateral side) and a compressive force on the facet capsule on the contralateral side.

19. Which of the following best describes the function of the sacrotuberous and sacrospinous ligaments? A. They prevent excessive counternutation of the sacrum on the innominates. B. They become most taut with end range of hip extension to effectively lock the sacrum and innominates together. C. They counterbalance the trunk forces that flex the sacral promontory. D. They form the superior border of the lesser sciatic foramen.

C Rationale: The strong sacrotuberous and sacrospinous ligaments have a primary role in counterbalancing the trunk forces that flex the sacral promontory.

13. If you needed to perform joint mobilization on the transverse processes of T9, you could locate them by which of the following landmarks? A. Just lateral to the spinous process of T11 B. Just lateral to the spinous process of T10 C. Just lateral to the spinous process of T9 D. Just lateral to the spinous process of T8

D Rationale: Due to the sharp angle of the spinous processes in the midthoracic spine, the tip of the spinous process would extend to the same level as the transverse process below. The angle of the spinous process varies throughout the thoracic spine, but in the midthoracic spine, the angle of the spinous process is the sharpest.

17. If a person stands and bends forward while attempting to touch his or her toes (keeping knees extended), this produces ____________________ at the innominates, ____________________ at the sacrum and flexion of the lumbar spine. A. posterior rotation, nutation B. anterior rotation, counternutation C. posterior rotation, counternutation D. anterior rotation, nutation

D Rationale: Forward flexion caused an anterior rotation of the pelvis accompanied by nutation of the sacrum. Nutation is the commonly used term for sacral motion when the sacral promontory moves anteriorly and inferiorly while the coccyx moves posteriorly in relation to the ilium.

20. Which of the following abdominal muscles would be active during trunk rotation to the right? A. Right internal oblique, right external oblique B. Left internal oblique, left external oblique C. Right internal oblique, left external oblique D. Left internal oblique, right external oblique

D Rationale: Rotation of the trunk occurs when the ipsilateral external oblique muscle and contralateral internal oblique muscle contract at the same time. For rotation to the right, this would mean contraction of the right external oblique and left internal oblique.

16. Which of the following statements is true concerning the surface of the sacroiliac joints? A. The sacral surface is formed from the fused bodies of S1 to S4. B. Both the sacral and innominate articular surfaces are covered with fibrocartilage. C. There is a pattern of elevations and ridges only on the sacral surfaces. D. The innominate articular surface is "C" shaped.

D Rationale: The articular surface of the sacrum is "C" shaped and covered with hyaline cartilage. The corresponding surface of the ilia is also "C" shaped but is covered with fibrocartilage. After puberty, grooves and ridges appear on both surfaces to restrict excessive motion.

24. Given the vertebral structure and orientation of the facet joints in the thoracic spine, which of the following motions would be most limited? A. Lateral flexion B. Rotation C. Distraction D. Extension

D Rationale: The close approximation of the thoracic spine spinous processes and 60° orientation of the facet joint allow for very limited motion into extension.

29. Describe the role of the disc in compressive loading of the spine. What happens under normal circumstances? What happens when normal forces are exceeded?

During compression of the vertebrae, stress through the vertebral bodies results in increased pressure on the nucleus. The pressure on the nucleus causes water to imbibe outward into the cartilaginous end plates, which creates a swelling pressure within the end plates. Simultaneously, the swelling nucleus creates tension in the surrounding annulus fibrosus, which pulls on the cartilaginous end plates to which it is attached. Because the cartilaginous end plates are able to undergo the least deformation of the vertebral tissues, the end plates are the first to fail under high levels of vertical compressive loading. The components of the disc are the last to fail and, in pure vertical compressive loading, are damaged only when there is first extensive damage of the cartilaginous end plate and vertebral body. Given the excellent mechanism for absorbing compressive stresses, the vertebral column rarely is damaged through compression alone.

33. What is the function of lumbopelvic rhythm? To what is this analogous?

Lumbopelvic rhythm is analogous to scapulohumeral rhythm, with its goal being to increase the available range of motion. Just as the scapula and humerus move together to increase the range available to the upper extremity, the pelvis and lumbar spine move in the same direction to increase the range available to the lower extremities or upper body. If the upper body is to be brought forward, as in leaning over to touch one's toes, the pelvis anteriorly tilts on the femurs (hip flexion), and the lumbar spine flexes simultaneously.

28. Give the new name acquired by each of the following ligaments as it passes cephalad to the axis: anterior longitudinal ligament, posterior longitudinal ligament, ligamentum flavum, and supraspinous.

The anterior longitudinal ligament becomes the anterior atlantoaxial ligament at C2. The posterior longitudinal ligament becomes the tectoral membrane at C2. The ligamentum flavum becomes the posterior atlantoaxial ligament at C2. The supraspinous ligament becomes the ligamentum nuchae at C7.

25. What parts of the typical vertebra are included in the anterior portion of the vertebra? In the posterior portion?

The anterior portion of the typical vertebra is composed of the vertebral body. The body has growth epiphyses (in the skeletally immature person) around the periphery of the superior and inferior vertebral plateaus, with a cartilaginous end plate in the center. The intervertebral disc is interposed between the bodies of most vertebrae. The posterior portion of the vertebral body is composed of the vertebral arch. The arch is formed by the pedicles anteriorly (which are sometimes considered part of the anterior vertebra) and the laminae posteriorly. The laminae begin posterior to the transverse processes and join to form the spinous process of the vertebra. The superior and inferior facets are part of the posterior portion of the vertebral arch.

26. What is the difference between the lamina and the pedicle of the vertebrae?

The pedicles are the two prominences by which the remainder of the arch is attached to the vertebral body. The laminae arise from the transverse processes and form the posterior wall of the spinal canal. The portion of the lamina between the superior and inferior facets is known as the pars interarticularis.

32. What is the predominant motion of the lumbar region? Where is the most motion occurring? Contrast the mobility and stability demands of this area.

The predominant motion of the lumbar region is flexion-extension, with only limited lateral flexion or rotation. What lateral flexion and rotation exist, however, are coupled opposite to the coupling in the cervical region. That is, lateral flexion of the lumbar vertebrae is associated with rotation of the vertebra to the opposite side. Once again, the coupling response may be dependent upon the state of flexion-extension of the region. The motions available in the lumbar region are largely the result of the facet joint orientation but are also influenced by the presence of the intertransverse ligament, which limits lateral flexion and to a lesser extent, rotation. In the flexion-extension range, flexion is more limited than extension. Flexion from neutral (neutral = slight posterior concavity) only proceeds to the point where the spine is straight. The lumbar spine is not normally able to reverse the lumbar curvature. The limitation in flexion is influenced by the large anterior vertebral height and the presence of the interspinous ligaments. The lumbar spine is generally fairly mobile (more so than the thoracic area), although at the base of the spine, it has greater stability demands placed upon it. Its mobility results from fewer bony restrictions (little impact of spinous processes and greater disc-to-body ratio. The contradictory demands of this region are typified by the fact that the greatest motion in the lumbar spine occurs at L5 to S1, although this is the lumbar interspace bearing the greatest amount of compressive force. The lumbar area received the additional support of the thoracolumbar fascia, which is thought to connect indirectly to and receive support from the transverse abdominis muscles.

31. Compare the mobility-stability of the cervical (C2 to C7) and thoracic regions, including the structures implicated.

The thoracic region, in general, is more stable and less mobile than the cervical region. In the thoracic region, additional bony checks to motion are provided by the long, downwardly pointing spinous processes (extension) and the ribs (lateral flexion). Additional checks in the thoracic region are provided by the tighter facet joint capsules. The facet joints in the thoracic region are very oriented to the frontal plane, enhancing lateral flexion but restricting flexion-extension. The cervical facets allow more freedom in all directions. The thoracic region is less mobile because it has a less favorable disc-to-body height ratio.

30. Identify and describe the three articulations of the atlantoaxial joint.

The three articulations of the atlantoaxial joint are the two lateral joints, which are formed by the facets (synovial), and the median articulation formed by the pivot of the dens (odontoid process) within the fibro-osseous ring of the anterior axis and the transverse ligament.