part of nuchal ligament A broad, fibrous, roughly triangular sagittal septum in the back of the neck, separating the right and left sides. It extends from the tips of the spinous processes of all the cervical vertebrae to attach to the entire length of the external occipital crest. Caudally it is continuous with the supraspinous ligament. BTO:0000952 BrendaTissueOBO ligamentum nuchae nape