Paired ligaments named for their colour, whose elastic fibres help the spine spring back upright after bending forward
Ligamentum flavum — high elastin content.
Anatomy · Joints & cartilage
Ligamentum flavum
Latin for 'yellow ligament'
Vertebral column · between laminae
The ligamenta flava (singular ligamentum flavum) are paired ligaments that join the laminae of adjacent vertebrae and form part of the back wall of the vertebral canal. They are called yellow ligaments because they contain a very high proportion of elastin. Their elasticity keeps the spine upright and helps it recover from flexion, and they are the last layer an epidural needle passes before it reaches the epidural space.
How to spot them
- ▸Paired sheets joining the lamina above to the lamina below, from the second cervical vertebra down to the sacrum
- ▸Yellow, because of elastic fibres, and unusually elastic for a ligament
- ▸Thickest in the lumbar region; they form the back wall of the vertebral canal
- ▸Lie deep to the interspinous ligaments and just behind the epidural space
What to know
The last barrier before the epidural space: an anaesthetist feels a loss of resistance after the needle has passed through it
Ligamentum flavum — the loss-of-resistance technique.
Thickening of it, with age, can narrow the vertebral canal and squeeze the nerves in the lower back
Ligamentum flavum — hypertrophy causing lumbar spinal stenosis.
It bridges the gap between the laminae of adjacent vertebrae and is absent between the skull and the atlas
Ligamentum flavum — it runs from C2/C3 downwards.
Unlike most ligaments, it is nearly 80 per cent elastin rather than collagen
Ligamentum flavum — the most elastic ligament of the body.
Key ideas
- Elastic ligament: it holds the vertebrae together at rest and stores energy in flexion, reducing the muscle effort needed to stand up straight.
Quick-fire facts
- •Flavum is Latin for yellow; the elastin in the ligament gives the yellow colour.
- •It contains about 80 per cent elastin and 20 per cent collagen, an unusually high proportion.
- •There is no ligamentum flavum between the skull and atlas or between the atlas and axis; they extend from C2/C3 to L5/S1.
- •It is thickest in the lumbar region.
- •On epidural insertion the needle passes skin, supraspinous ligament, interspinous ligament, ligamentum flavum and then the epidural space.
- •Hypertrophy of the ligamentum flavum can cause spinal stenosis.
- •The other main ligaments of the spine are the anterior and posterior longitudinal ligaments and the supraspinous and interspinous ligaments.
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