Which ligaments limit flexion?

• A. anterior longitudinal ligament
• B. interspinous and ligamentum nuchae
• C. supraspinous ligament
• D. posterior longitudinal ligament

Answer: (B)

When the spine flexes, the posterior structures become taut and act as the main brakes to forward bending. The interspinous ligaments run between the spinous processes, and the ligamentum nuchae is a strong cervical extension of that posterior tension. Together they resist and limit further flexion, helping to prevent the spine from bending too far forward. This makes them the best answer for which ligaments primarily constrain flexion.

For context, other ligaments have different roles: the anterior longitudinal ligament mostly resists extension, while the posterior longitudinal ligament and the other posterior ligaments (like the supraspinous and ligamentum flavum) also contribute to limiting flexion, but the combination of interspinous plus ligamentum nuchae is the most directly involved in stopping forward bending across much of the spine, especially in the neck region.