Ligamentum flavum connects the back of one vertebral bone to the vertebra adjacent
to it. The ligamentum flava are the series of elastic bands that run throughout the spine from the cervical spine segment C2 to the sacrum segment S1, keeping us upright. The ligamentum flavum is quite elastic and remains taut throughout the spine as it connects from one vertebral bone's facet capsule and lamina to another.
Cervical spine ligamentum flava are thin, thoracic are thicker, and lumbar are thickest.