most severe. Location The location of the herniation can also be described using the MSU Classification for herniated discs. This classification describes how far away from mid-line a disc protrusion is using a grade of A, B, or C. Grade A describes a herniation at midline. Grade C herniations are the most lateral and protrude into the intervertebral foramen (through which spinal nerves travel). Grade B herniated discs are those located between grade A and C, using the facet joint as the landmark for the lateral border. MSU Classification is primarily used for classifying herniated discs in the lumbar spine. Causes Many back injuries share similar causes. Strains and sprains to the back muscles can be caused by improper movements while lifting heavy loads, overuse of a muscle, sudden forceful movements, or direct trauma. Herniated discs are associated with age-related degeneration, trauma such as a fall or car accident, and bending or twisting while lifting heavy weights. Common causes of vertebral fractures include trauma from a direct blow, a compression force resulting in improper or excessive axial loading, and hyper-flexion or hyper-extension. Vertebral fractures in children or elderly individuals can be related to the development or health of their spine. The most common vertebral fracture in children is spondylolysis which can progress to spondylolisthesis. The immature skeleton contains growth plates which have not yet completely ossified into stronger mature bone. Vertebral fractures in elderly individuals are exacerbated by weakening of the skeleton associated with osteoporosis. Diagnosis Diagnosis of a back injury begins with a physical examination and thorough medical history by health-care personnel. Some injuries, such as sprains and strains or herniated discs, can be diagnosed in this manner. To confirm these diagnoses, or to rule out other injuries or pathology, imaging of the injured region can be ordered. X-rays are often used to visualize pathology of bones and can be ordered when a vertebral fracture is suspected. CT scans produce higher resolution images when compared to x-rays and can be used to view more subtle fractures which may otherwise go undetected on x-ray. MRI is commonly referred to as the gold standard for visualizing soft tissue and can be used to assist with diagnosing many back injuries, including herniated discs and neurological disorders, bleeding, and edema. Prevention Suggestions for preventing various back injuries primarily address the causes of those injuries. The risk for back sprains and strains may be