happens when the outer anulus fibrosus becomes weakened and leaks the contents of the nucleus pulposus out into the spinal canal or the intervertebral foramen. The adjacent vertebrae are connected by ligaments that run the length of the vertebral column. The anterior longitudinal ligament runs around the anterior side of the vertebral bodies and resists backward bending. The supraspinous ligament is located on the back side of the vertebral column and supports the spine during forward bending. It forms the nuchal ligament at the top of the spine, where the spine attaches to the back of the skull. There is also a posterior longitudinal ligament that is found inside the vertebral column. Behind the spinal cord inside the spinal column is the ligamentum flavum that connects the lamina of the adjacent vertebrae.
RIBCAGE AND STERNUM The thoracic cage is part of the axial skeleton. It consists of twelve paired ribs and the sternum or breastplate. The ribs are all attached to the twelve thoracic vertebrae; its function is to protect the heart and the lungs. The sternum has three parts: the manubrium, the body, and the xyphoid process. The manubrium is at the top and is a wide/flat bone. The top of it has a shallow, U-shaped border called the jugular (suprasternal) notch. On either side of it is the clavicular notch, where the sternoclavicular joint is located (the joint between the sternum and the clavicle). The first ribs have attachments to the manubrium. The body of the sternum is the largest part. It joins the manubrium at the sternal angle, forming a slight bend. The second rib attaches to the sternal angle. Ribs three through seven will attach to the sternal body; below this is the xyphoid process, which is mainly cartilaginous until a person reaches the middle age years of their life. Ribs are not long bones rather curved, flat bones that form the wall of the thorax. They each articulate in the back to the twelve thoracic vertebrae, attaching anteriorly to the sternum via the costal cartilages. Only ribs 11 and 12 are free-floating and do not connect anteriorly. The
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