Define the following terms and discuss their clinical significance.

1. Name the ligaments of the L4/5 segments from anterior to posterior

2. Give the most likely function of the ligamentum flavum

3. Give two functions of the anulus fibrosis

4. Give two functions of the nucleus pulposus

5. List three differences between disc degeneration and disc degradation

6. List three differences in the anatomy of the L5/S1 segment and that of the L4/5 segment

7. Give the two main structures that limit right axial (pure) rotation at L4/5

8. Describe the differences between axial (pure) rotation and physiological rotation

1. Name the ligaments of the L3/4 segments from anterior to posterior:

• Anterior longitudinal
• Anterior anulus fibrosis
• Lateral anulus fibrosis
• Posterior anulus fibrosis
• Posterior longitudinal
• Intertransverse
• Ligamentum flavum
• Interspinous
• Supraspinous

2. Give the most likely function of the ligamentum flavum

   • The elastic recoil prevents the ligament from buckling into the spinal canal during extension

3. Give two functions of the anulus fibrosis

• Together with the nucleus pulposis, it increases range of motion over what it would be if the disc was absent
• Limit range of motion as it stretches anulus
• Constrain and contain the nucleus pulposis
• Possible proprioceptive function

4. Give two functions of the nucleus pulposis

• Together with the anulus it increases the range of motion over what it would be if the disc was absent
• To brace the anulus
• To disperse compression forces

5. List three differences between disc degeneration and disc degradation

• Degeneration is a universal phenomenon, degradation is pathological
• There is increased disc height with degeneration and decreased height with degradation
• There is no herniation of nuclear material with degeneration but there is with degradation

6. List three differences between the anatomy of the L5/S1 segment and the L4/5.

• The presence of a strong iliolumbar ligament at L5/S1
• A wedge shaped L5/S1 disc
• A wedge shaped L5 centrum
• More coronal zygopophyseal joints at L5/S1
• The absence of a supraspinous ligament at L5/S1 (according to some anatomists)

7. Give the two main structures that limit right axial (pure) rotation

• The left zygopophyseal joint
• The right superoanteriorly orientated lamellae of the anulus fibrosis

8. Describe the differences between axial (pure) rotation and physiological rotation in the lumbar spine

• There is normally only about 1 degree of pure rotation and upwards of three of physiological rotation
• Pure rotation is uncoupled, while physiological rotation is coupled rotation and side flexion