Despite the elastic and flexible nature of the ligament, at neutral position, the ligament has pretension preventing it from buckling. At lumbar vertebra this pretension is provided by the traction and tension forces applied by muscles on the Thoracolumbar fascia by the supraspinous , interspinous ligaments to ligamentum flavum causing pretension in the neutral position (interspinous_supraspinous thoracolumbar ligamentous complex )
At each intersegmental level the ligamentum flavum is a paired structure being represented symmetrically on both sides.
In the neck region the ligaments are thin, but broad and long; they are thicker in the thoracic region, and thickest in the lumbar region.
The ligament flavum arises from the lower half of the anterior surface of the lamina above and attaches to the posterior surface and upper margin of the lamina below, forming a cup-like grasp on the upper border of the lamina below.
On each side the ligament divides into two portions:
- The medial portion : passes to the back of the next lower lamina and across the gap between the adjacent vertebrae fusing with the interspinous ligament
- The lateral portion : passes in front of the facet joint where it attaches to the anterior aspect of the inferior and superior articular processes and forms the anterior capsule. The most lateral fibers extend beyond the superior articular process to the pedicle below.
The marked elasticity serves to preserve the upright posture and to assist the vertebral column in resuming it's shape after flexion. It resists excessive separation of the adjacent vertebral lamina and prevents buckling of the ligament into the spinal canal during extension, preventing canal compression. The lateral portion of the ligament prevents the anterior capsule of the facet joint being nipped within the joint cavity during movement.
The body goes through several changes as a person ages. Some of these changes occur because of the continued wear that is placed on the body over long periods of time. The neck and back are especially susceptible to these changes since they are responsible for supporting the majority of the body’s weight and movements.over time,
Ligamentum flavum can lose strength and elasticity, causing it to thicken and buckle towards the spinal column this is due to loss of elastic fibers which at same time increase in the thickness of collagen fibers ,These events cause deposition of Ca+2 in the ligament. Calcification of the ligament causes hypertrophy and can lead to spinal canal stenosis (narrowing of the spinal canal) which can sometimes cause pain.
If the ligamentum flavum buckles to the point that it impinges a spinal nerve, a patient may experience the following symptoms of spinal stenosis:
- Localized pain
- Radiating pain (depending on the location of the spinal stenosis, the pain could radiate into the shoulders, arms, ribs or legs)
Hypertrophy of this ligament may cause spinal stenosis because it lies in the posterior portion of the vertebral canal. Increased expression of TIMP-2 in ligamentum flavum fibroblasts is associated with fibrosis and hypertrophy of the ligamentum flavum in patients with spinal stenosis.
Many causes of neck and back pain are directly related to the ligamentum flavum. Though the anatomy of the spine is quite complex, treating conditions that affect it does not have to be. Unfortunately, there is little to no regeneration power of elastin tissue at ligamentum flavum, loss of elastin tissue cannot be recovered.
The combination of MRI and computed tomography seems the most useful for the precise diagnosis of OLF.
- Nikolai Bogduk. Clinical and Radiological Anatomy of the Lumbar Spine 5th Edition.Churchill Livingstone: Elsevier. Feb 2012.
- Vleeming A ,Mooney V . Movement, Stability & Lumbopelvic Pain 2nd Edition . Philadelphia.Churchill Livingstone .1st March 2007
- Park J B, Lee J K, Park SJ, Riew KD .Hypertrophy of ligamentum flavum in lumbar spinal stenosis associated with increased proteinase inhibitor concentration.The Journal of Bone and Joint Surgery-American . 2005 Dec:87(12):2750-7.
- J. Hanakita ,H. Suwa , F. Ohta , S. Nishi , H. Sakaida . Neuroradiological examination of thoracic radiculo-myelopathy due to ossification of the ligamentum flavum .Neuroradiology Jan 1990 :32 (1):38-42.