Related Experiment Video
Updated: Jun 6, 2026

Laminectomy for the Removal of Thoracic Ossification of the Ligamentum Flavum (TOLF) Using Ultrasonic and Conventional Osteotomes
Published on: April 21, 2023
Is ossification of posterior longitudinal ligament an enthesopathy?
Jian Chen1, Dianwen Song, Xinwei Wang
1Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, 415# Fengyang Road, Shanghai, Peoples Republic of China.
Abstract:
The purpose of this study was to investigate the relationship of ossification of posterior longitudinal ligament (OPLL) with enthesis, the site where the posterior longitudinal ligament (PLL) attaches to the vertebral body, by multi-detector CT reconstruction images. Twenty-nine patients with OPLL were studied. According to the plaques' continuity to the vertebral body, OPLL plaques were classified into two categories: "free" and "contiguous". A "broken sign" was defined as a crack between two plaques. The sites where each "contiguous" plaque attached to the vertebral body were then analysed. There were 78 ossified plaques in total, and six were "free". There were eight cases with a "broken sign", including six "free" ones. The site where all 72 "contiguous" plaques attached to the vertebral body included the zone where the PLL enthesis was situated, while other zones were included in only part of the plaques. Our conclusion was that there might be no real "free type" ossified plaques, and OPLL could start from enthesis, which indicated OPLL could be a kind of enthesopathy.
Related Concept Videos
The Auditory Ossicles
The aptly named stapes look very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in...
Pleiotropy
Development of the Limb Synovial Joints
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
Bone Formation by Endochondral Ossification
Bone Formation by Intramembranous Ossification
The process begins when mesenchymal cells in the embryonic skeleton gather together and differentiate into osteogenic cells, which then develop into...