Calcification and ossification affect a variety of posterior spinal ligaments and tissues. Ossification of the posterior longitudinal ligament is a characteristic disorder of the spine that may be associated with significant neurologic findings. Its radiographic appearance is diagnostic and consists of a linear band of ossification along the posterior margin of the vertebral bodies and intervertebral discs, particularly in the cervical spine. Arachnoiditis ossificans is a rare condition that leads to extensive ossification in the arachnoid membrane, especially in the thoracic spine, and it produces significant symptoms and signs. Osseous proliferation at the cephalad and caudad attachments of the ligamentum flavum is a frequent finding that is generally of no significance. When extensive, however, such ossification in the thoracic spine leads to neurologic manifestations and is accompanied by involvement of nearby tissues and ligaments and, in some cases, diffuse idiopathic skeletal hyperostosis. Calcification in the ligamentum flavum is usually observed in the cervical spine and is associated with calcium hydroxyapatite crystal deposition or, more infrequently, calcium pyrophosphate dihydrate crystal accumulation. A nodular radiodense collection is the typical radiographic abnormality. The candidate will learn the mechanics of putting together an electronic poster presentation in lecture type format. This will be an official peer-reviewed publication. The publication will be a favorable addition to the candidate's CV. The candidate will be the first author, and I am the second author. A candidate is not limited to completing one project. He/she can do as many as they like! (There are always topics to teach about) The candidate, myself, King's College Hospital Department of Radiology and King's College all benefit from this publication.