Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.




Kyphosis is the extreme curvature of the upper back also known as a hunchback.


The upper back bone (thoracic region), is normally curved forward. If the curve exceeds 50° it is considered abnormal (kyphotic).

Causes and symptoms

Kyphosis can be divided into three ages of acquisition—birth, old age, and the time in between.
  • Spinal birth defects can result in a fixed, exaggerated curve. Vertebrae can be fused together, shaped wrong, extraneous, or partially missing. Congenital and hereditary defects in bone growth weaken bone and result in exaggerated curves wherever gravity or muscles pull on them. Dwarfism is such a defect.
  • During life, several events can distort the spine. Because the natural tendency of the thoracic spine is to curve forward, any weakness of the supporting structures will tend in that direction. A diseased thoracic vertebra (a spine bone) will ordinarily crumble its forward edge first, increasing the kyphotic curve. Conditions that can do this include cancer, tuberculosis, Scheuermann's disease, and certain kinds of arthritis. Healthy vertebra will fracture forward with rapid deceleration injuries, such as in car crashes when the victim is not wearing a seat belt.
  • Later in life, kyphosis is caused from osteoporosis, bone weakness, and crumbling forward.
The stress caused by kyphosis produces such symptoms as an increase in musculoskeletal pains, tension headaches, back aches, and joint pains.


A quick look at the back will usually identify kyphosis. X rays of the spine will confirm the diagnosis and identify its cause.


Congenital defects have to be repaired surgically. The procedures are delicate, complicated, and lengthy. Often orthopedic hardware must be placed to stabilize the back bone. At other times, a device called a Milwaukee brace can hold the back in place from the outside. Fitting Milwaukee braces comfortably is difficult because they tend to rub and cause sores.
Kyphosis acquired during the younger years requires treatment directed at the cause, such as medications for tuberculosis. Surgical reconstruction or bracing may also be necessary.
Kyphosis induced by osteoporosis is generally not treated except to prevent further bone softening.


Congenital kyphosis may be alleviated to some extent by surgery and bracing. Kyphosis occurring later in life may worsen over time.


Preventing osteoporosis is within the grasp of modern medicine. Menopausal women must start early with estrogen replacement, calcium supplementation, and appropriate exercise. The treatment must continue through the remainder of life. Evidence suggests that a high calcium intake even during younger years delays the onset of symptomatic osteoporosis. Dairy products are the major dietary sources of calcium.



Arthritis Foundation.1300 W. Peachtree St., Atlanta, GA 30309. (800) 283-7800.
National Osteoporosis Foundation. 1150 17th St., Suite 500 NW, Washington, DC 20036-4603. (800) 223-9994.
Osteoporosis and Related Bone Diseases-National Resource Center. 1150 17th S. NW, Ste. 500, Washington, DC 20036. (800) 624-2663.

Key terms

Congenital — Present at birth.
Dwarfism — A congenital disease of bone growth that results in short stature and weak bones.
Orthopedic — Refers to surgery on the supporting structures of the body-bones, joints, ligaments, muscles.
Osteoporosis — A weakening of bones due to calcium loss that affects post-menopausal women.
Scheuermann's disease — Juvenile kyphosis due to damaged bone in the spinal vertebrae.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


abnormally increased convex curvature of the thoracic spine as seen from the side; it may be the result of an acquired disease, an injury, or a congenital disorder or disease. It never develops from poor posture. One of the most common causes is postmenopausal osteoporosis accompanied by anterior vertebral body wedge-compression fractures. adj., adj kyphot´ic.

Kyphosis sometimes occurs with certain forms of poliomyelitis and with diseases that cause bone destruction, as happens in osteitis deformans (paget's disease). An injury, such as a fracture of the spine, treated improperly or not at all, may also result in hunchback. Some rare cases are caused by congenital deformities and diseases. One example, achondroplasia, or fetal rickets, is a congenital bone disorder that affects growth and bone formation. There are no specific symptoms besides back pain and increasing immobility of the spine. Symptoms vary with the cause, and any back pain or injury should be investigated.
Kyphosis. From Frazier et al., 1996.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


1. An anteriorly concave curvature of the vertebral column; the normal kyphoses of the thoracic and sacral regions are retained portions of the primary curvature (kyphosis) of the vertebral column.
2. A forward (flexion) curvature of the spine; the thoracic spine normally has a mild kyphosis; excessive forward curvature of the thoracic spine may indicate a pathologic condition.
[G. kyphōsis, hump-back, fr. kyphos, bent, hump-backed]
Farlex Partner Medical Dictionary © Farlex 2012


Abnormal rearward curvature of the spine, resulting in protuberance of the upper back; hunchback.

ky·phot′ic (-fŏt′ĭk) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Humpback, spinal kyphosis Orthopedics Angular curvature of the spine, with a posterior convexity, usually situated in the thoracic region involving a variable number of vertebrae Etiology TB, osteoarthrosis, rheumatoid arthritis, poor posture
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


1. An anteriorly concave curvature of the vertebral column, such as normally occurs in the thoracic and sacrococcygeal regions.
2. Hyperkyphosis; excessive anteriorly concave curvature of a part of the spine, usually thoracic.
Compare: hyperkyphotic
[G. kyphōsis, hump-back, fr. kyphos, bent, hump-backed]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
Enlarge picture


(ki-fo'sis) [Gr., humpback]
1. The normal posterior curvature of the thoracic and sacral spine.
2. An exaggeration or angulation of the posterior curve of the thoracic spine, giving rise to the condition commonly known as humpback, hunchback, or Pott's curvature. It may be due to congenital anomaly, disease (tuberculosis, syphilis), malignancy, or compression fracture. This term also refers to an excessive curvature of the spine with convexity backward, which may result from osteoarthritis or rheumatoid arthritis, rickets, or other conditions.
Synonym: humpback; spinal curvature See: illustrationkyphotic (-fot'ik), adjective
Medical Dictionary, © 2009 Farlex and Partners


An abnormal degree of backward curvature of the part of the spine between the neck and the lumbar regions. Backward curvature is normal in this region and kyphosis is an exaggeration of the normal curve. It is commonly the result of bad postural habits in adolescence or of OSTEOPOROSIS. From the Greek kyphos , meaning bowed or bent.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


1. An anteriorly concave curvature of the vertebral column; normal kyphoses of the thoracic and sacral regions are retained portions of the primary curvature of the vertebral column.
2. Forward curvature of spine.
[G. kyphōsis, hump-back, fr. kyphos, bent, hump-backed]
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Incidence, risk factors, and natural course of proximal junctional kyphosis: surgical outcomes review of adult idiopathic scoliosis.
Combined posterior instrumentation and anterior interbody fusion for active tuberculous kyphosis of the thoraco-lumbar spine.
In the present study, patients in the study group underwent 10 sessions of a PT program consisting of superficial heating (hot pack), analgesic current (TENS), and deep heating (US).Upon completion of the PT sessions, significant improvements were recorded in the sagittal spinal alignment in terms of LSA, lumbar lordosis, and thoracic kyphosis. It was also observed that the treatment applied only to the lumbar paravertebral region positively affected the thoracic spine.
Reciprocal angulation of vertebral bodies in a sagittal plane: approach to references for the evaluation of kyphosis and lordosis.
--control group with thoracic kyphosis [greater than or equal to] 42[degrees] (as measured between the C7 and Th12 and the apex of kyphosis), with 43 girls and 34 boys.
The common initial symptoms of our patients were short stature and gait disturbance and all have skeletal manifestations; as short trunk dwarfism, pectus carinatum, kyphosis, gibbous, scoliosis, genu valgum, coxa valga, hypermobile joint.
Compared with never-users, remote past HT users had 3.0 degrees less kyphosis, in minimally-adjusted models (P = 0.01); the correlation was attenuated to 2.8 degrees less kyphosis in fully-adjusted models (P = 0.02).
Pedicle subtraction osteotomy (PSO), a V-shaped wedge resection of the vertebral body, is the most popular technique in the surgical treatment of kyphosis in AS patients.[10],[11] In the PSO procedure, correction is obtained through a closing wedge osteotomy that hinges on the anterior column of the vertebral body.
The most frequent deviations observed in youngsters are scoliosis, kyphosis, and lordosis.
Harrington distraction instrumentation was later noted to cause fatback syndrome, a term used to describe the iatrogenic kyphosis that can result from this instrumentation system.
(i) General structural spinal abnormalities like scoliosis or kyphosis.
MRI of the cervical spine revealed spinal cord compression at the level of the foramen magnum secondary to a craniocervical junction anomaly with severe kyphosis of the upper cervical spine at the level of C3-C4 (Figure 1).