Ligaments

Written by Keith Bridwell, MD
Reviewed by Mary Rodts, DNP

Ligaments are fibrous bands or sheets of connective tissue linking two or more bones, cartilages, or structures together. One or more ligaments provide stability to a joint during rest and movement. Excessive movements such as hyper–extension or hyper–flexion, may be restricted by ligaments. Further, some ligaments prevent movement in certain directions.

Three of the more important ligaments in the spine are the Ligamentum Flavum, Anterior Longitudinal Ligament and the Posterior Longitudinal Ligament.

Primary Spinal Ligaments Include:

Ligament Spinal Region Limits…
Alar Axis – skull Head rotation & lateral flexion
Anterior Atlantoaxial Axis & Atlas Extension
Posterior Atlantoaxial Axis & Atlas Flexion
Ligamentum Nuchae Cervical Flexion
Anterior Longitudinal Axis – Sacrum Extension & reinforces front of annulus fibrosis
Posterior Longitudinal Axis – Sacrum Flexion & reinforces back of annulus fibrosis
Ligamentum Flavum Axis – Sacrum Flexion
Supraspinous Thoracic & Lumbar Flexion
Interspinous Lumbar Flexion
Intertransverse Lumbar Lateral flexion
Iliolumbar Sacroiliac joints Stability & some motion
Sacroiliac Sacroiliac joints Stability & some motion
Sacrospinous Sacroiliac joints Stability & some motion
Sacrotuberous Sacroiliac joints Stability & some motion
Ligaments of the Back of the Cervical and Upper Thoracic Spine
1. Supraspinous Ligament (flexion)
2. Ligamentum Nuchae (fibrous membrane)

Ligament Systems – Atlas and Axis
As mentioned in the Vertebral Column, the Atlas (C1) and Axis (C2) are different from the other spinal vertebrae. The upper cervical ligament system is especially important in stabilizing the upper cervical spine from the skull to C2. Although the cervical vertebrae are the smallest, the neck has the greatest range of motion.

Occipitoatlantal Ligament Complex (Atlas)
These four ligaments run between the Occiput and the Atlas:

Occipitoaxial Ligament Complex (Axis)
These four ligaments connect the Occiput to the Axis:

Altantoaxial Ligament Complex (Axis)
These four ligaments extend from the Atlas to the Axis:

Cruciate Ligament Complex
These ligaments help to stabilize the Atlantoaxial (Axis) complex:

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