The anterior longitudinal ligament (ALL) runs along the anterior surface of the vertebral bodies (firmly united to the periosteum) and intervertebral discs (attaching to the anterior annulus). It ascends from the anterosuperior portion of the sacrum superiorly to become the anterior atlantooccipital membrane at the level of the anterior arch of C1 (atlas) .
It can be divided into three distinct layers .
- superficial: traverses 3-4 vertebrae
- intermediate: covers 2-3 vertebrae
- between individual vertebrae, it either blends into the periosteum or inserts anteriorly
- the first ALL layer is typically affected in DISH