Kyphosis is a condition characterized by an abnormally exaggerated forward curvature of the upper back region, giving it a rounded, or humpback, appearance. The condition may develop among children as a result of congenital or developmental problems, or it may develop later in life as a result of injury or degenerative or inflammatory diseases that affect the bones of the spine, according to MayoClinic.com.
Congenital and Hereditary Causes
Certain congenital conditions that develop in utero or during childbirth can cause kyphosis. For example, according to Children’s Hospital Boston, osteogenesis imperfecta—a congenital disease that causes children to have extremely fragile, brittle bones—can increase the risk of spinal fracture, in turn predisposing them to developing kyphosis. Spina bifida, another congenital condition characterized by incomplete development of the spinal cord, can also cause kyphosis, according to MayoClinic.com.
Doctors believe that hereditary factors are one possible cause for a special type of kyphosis known as Scheuermann's kyphosis, as the condition appears to run in families.
Osteoporosis
According to the University of Maryland Spine Program, osteoporosis—a progressive condition that causes loss of bone tissue and bone thinning over time—is the most common cause of adult kyphosis. As the bones in the spinal column weaken, they are more susceptible to fracture and compression. This degeneration and brittleness can ultimately cause the upper back to hunch forward.
Paralyzing Conditions
Paralysis causes a stiffening and immobility of the spinal vertebrae. Any medical condition that results in partial or total paralysis of the spine can cause kyphosis. For example, cerebral palsy—a group of neurological disorders that impairs muscle coordination and movement—and polio—a viral disease that can attack the nerves of the muscles and cause paralysis—may both lead to the development of kyphosis, according to MayoClinic.com.
Infection
Some viruses and bacteria can infect the spine, leading to structural damage that increases the risk for kyphosis. According to MayoClinic.com, tuberculosis of the spine—an infection caused by Mycobacterium tuberculosis bacteria—causes destruction of the vertebral bones. As these bones deteriorate, they may fracture or collapse, leading to the characteristic hunchback appearance associated with kyphosis.
Inflammatory Arthritis
Ankylosing spondylitis—a chronic type of inflammatory arthritis that causes swelling to occur between bones in the spinal column and in nearby joints—can cause kyphosis, according to MayoClinic.com. Chronic inflammation of the tissues surrounding the vertebrae of the spine can cause pain, stiffness and loss of mobility. Patients may adopt an abnormal slouching posture to minimize the discomfort caused by this inflammation, in turn putting a strain on and weakening the ligaments and tendons that normally help to support the spine. Postural changes can also affect the alignment of vertebrae. All of these factors work together to cause an excessive rounding of the upper spine.
Cancer and Cancer Treatment
Tumors that form in or near the spine can push one or more vertebrae out of place, sometimes resulting in kyphosis. According to the University of Maryland Spine Program, children who received radiation treatment to the axial skeleton—the human skeleton consisting of the bones of the head and trunk, including the skull, mandible, sternum, ribs, vertebral column and sacrum—are also at risk of developing kyphosis, as the high-energy radiation waves can interfere with the normal development of vertebral bones.
Back Injury
Injury or trauma to the spine as a result of a fall, sports injury or motor vehicle collision can cause kyphosis. According to the University of Maryland Spine Program, in approximately 90 percent of patients with fractures to the lower or thoracic spine, mild to severe kyphosis develops. Any back injury can cause damage to the nerves, vertebral disks and other supportive structures and to muscles in the back. Over time, these structures may deteriorate and weaken, leading to progressively more severe kyphosis.
