Protruding bones in the back may be caused by the following reasons. 1. It may be due to the patient being too thin. Some patients, due to excessive weight loss or the presence of wasting diseases, like diabetes, tuberculosis, tumors and the like, may cause the subcutaneous fat of the whole body to become very thin. The normal bony protrusions of the back, such as the bilateral scapulae, spinal spines, ribs and so on, may become very prominent. 2, this condition may be caused by deformities related to the spine. For example, scoliosis may cause a series of bones, including the spine, to become deformed, leading to protrusion. 3. This condition may also be caused by old injuries. For example, an old fracture in the above mentioned area may cause a kyphosis of the spine. 4. This condition may also be caused by a local bone occupational disease. For example, the presence of a bone tumor within the bone of the back may produce similar symptoms.