Yellow ligaments (ligamenta flava)

The yellow ligaments (ligamenta flava) are thin, broad, and relatively strong paired fibrous bands that stretch between the laminae of adjacent vertebrae. Each yellow ligament extends from the posterior and superior aspects of the lamina of the vertebra below to the anterior and inferior surfaces of the lamina of the vertebra above.

The first pair is located between the first two cervical vertebrae (C1/C2). In the cranial direction, the yellow ligaments continue as the posterior atlantooccipital membrane, which stretches between the atlas (C1) and the occipital bone of the skull.

Some authors suggest that the yellow ligaments at the C1 - C2 level should rather be considered the posterior atlantoaxial membrane, as they appear thin and membranous. In our 3D model, the first pair of the yellow ligaments is shown between the axis (C2) and the C3 vertebra - it is the first pair that unequivocally represents these ligaments.

The yellow ligaments are named so because they actually appear yellowish. They are highly elastic structures, containing a high amount of elastin and a low amount of collagen. Elastin not only gives the ligaments their characteristic yellow color but also provides flexibility, allowing them to return the spine to its anatomical position.

Functionally, the yellow ligaments resist the separation of the laminae during flexion of the spine and limit hyperflexion. They also aid in the extension of the spine, helping the spine to return to its anatomical position after flexion.

Additionally, these ligaments contribute to maintaining an upright posture and preserving the natural curvatures of the spine. Besides the mentioned functions, the yellow ligaments and laminae of the vertebral arches together form the posterior wall of the vertebral canal.

Note: These ligaments are present throughout most of the spine. The last pair can be found between the fifth lumbar vertebra (L5) and the sacrum.