Your thoracic vertebrae comprise the middle segment of the spine, where thoracic herniated discs may occur. These 12 vertebrae are located between the cervical (neck) area and the lumbar (lower back area). These upper back vertebrae run from the spot where the neck meets the back above the shoulder blade level and continue down to the bottom of the rib cage. The spinal bones are smaller in size at the top and grow larger down toward the lumbar area. These vertebrae have facets on the sides to interact with the ribs. A thoracic herniated disc may be caused by injury like a fall, strain or twist, or due to a cracked vertebra, a disc or discs weakened by aging, scar tissue or other causes.