Scoliosis Key Terms

Scoliosis and scoliosis research can be a complex field with many technical terms which may be unfamiliar – this keyword list is intended to help you familiarise yourself with the terminology you will encounter on this site and others. As always, if you have questions about scoliosis, or perhaps you feel another professional has not explained your condition in a way you can understand, feel free to get in touch.


Adolescent Scoliosis – A lateral (sidewards) spinal curvature that appears before the onset of puberty and before skeletal maturity.

Adult Scoliosis – scoliosis which is present after skeletal maturity.

Anterior – The front portion of the vertebral body. It may also indicate the position of one structure relative to another.

Apex of Scoliosis – The area of greatest curvature or displacement from the centreline of the body.

Apical Vertebra – When referring to scoliosis, it is the vertebra with the greatest distance from the centreline and has the most rotation. The Apicial Vertebra is therefore at the centre of the Apex of Scoliosis.

Body Cast – A cast which surrounds the chest, abdomen and pelvis. It may also include the shoulders. This may be used to correct scoliosis in very young patients or for postoperative spinal immobilization.

Bone Graft – Human bone, which is harvested from one location in an individual and placed in another individual (allograft bone) or in a different location in the same individual (autogenous bone). A common place to take autogenous bone graft from is the anterior and posterior iliac crests (the hip bones).

Bone Spur – An overgrowth of bone in response to stress or injury.

Cervical Spine – Seven spinal segments (C1-C7) between the base of the skull and the thoracic spine.

Cervicothoracolumbosacral orthosis (CTLSO) – A type of brace which immobilizes the cervical, thoracic and lumbar spine. This may be used to help stabilize/ prevent progression of scoliosis curve(s) while a child is growing, or to immobilize the spine after surgery.

Cobb angle: This is a measurement of the size of the spinal curve. The curve is measured on an X-ray of the spine. A curve of 10 degrees or less is classed as normal, a curve of between 10 and 30 degrees is classed as mild, a curve of over 60 degrees is classed as severe. Different specialists can measure the Cobb angle in slightly different ways and getting a slightly different number is not unusual, especially if the curve is large.

Compensatory Curve – In scoliosis a compensatory curve is a secondary curve located above or below the main curvature, which develops in order to maintain normal body alignment.

Congenital scoliosis – Scoliosis due to bony abnormalities of the spine present at birth. These anomalies are classified as failure of vertebral formation and/or failure of segmentation.

Decompensation – In scoliosis, this refers to loss of spinal balance when the thoracic cage is not centered over the pelvis.

De-novo scoliosis: De novo or degenerative scoliosis is a curvature of the spine that develops in a previously straight spine because of ageing or premature ageing. It usually develops late in life.

Disc Degeneration – The loss of the fluid content, structure and functional integrity of the disc. A common problem, not just in scoliosis.

Discectomy – Removal of all or part of an intervertebral disc (the soft tissue that acts as a shock absorber between the vertebral bodies). This may be done for fusion or because of herniation.

Double curve – When two scoliotic curves exist in the same spine.

Double major curve – Describes a scoliosis in which there are two structural curves (as opposed to one structural and one compensatory) which are usually of equal size.

Double thoracic curve – A scoliosis with a structural upper thoracic curve, as well as a larger, more deforming lower thoracic curve and a relatively non-structural lumbar curve.

Flatback Syndrome/Fixed Sagittal Imbalance Syndrome – Forward posture usually due to a flattened lumbar spine from postoperative or degenerative changes. When viewed from the side, the patient’s head may be several centimeters in front of their hips..

Fusion – The uniting of two or more bony segments.

Hyperkyphosis – “Kyphosis” refers to an abnormal increase in the forward curvature of the spine, Hyperkyphosis is when this condition exists to a significant degree.

Hysterical scoliosis – A non-structural deformity of the spine that develops as a manifestation of a psychological disorder.

Idiopathic scoliosis – A structural spinal curvature for which the exact cause has not been established. This is the most common form of scoliosis.

Idiopathic: Most cases of scoliosis are idiopathic. This means that no one knows what caused the curve  – more research is being done as to the cause, but at the moment the reason is unclear.

Infantile scoliosis – A curvature of the spine that develops before three years of age.

Juvenile scoliosis – Scoliosis developing between the ages of three and ten years.

Kyphoscoliosis – A structural scoliosis associated with increased kyphosis.

Lordoscoliosis – A lateral curvature of the spine associated with increased lordosis.

Lordosis: is the normal inward curve of the middle and lower back below where the rib cage stops. An unusually large lordosis is sometimes called sway back or hollow back. Patients with large lordosis often have a more forward tilted pelvis (the pelvis is the large frame at the base of the spine – the legs are attached to it).

Lumbar Curve – A spinal curvature whose apex is between the first and fourth lumbar vertebrae (also known as lumbar scoliosis).

Lumbar Spine – Five mobile segments of the lower back (L1 to L5). These are the largest of the vertebral segments and provide most of the bending and turning ability of the back, in addition to bearing most of the weight of the body.

Lumbosacral Curve – A lateral curvature with its apex at the fifth lumbar vertebra or below (also known as lumbosacral scoliosis).

Primary Curve – The first, or earliest, curve to appear.

Risser Sign – Used to evaluate skeletal and spinal maturity, this refers to the appearance of a crescent-shaped line of bone formation which appears across the top of each side of the pelvis on plain x-ray.

Rib prominence: With scoliosis there is a twist (rotation) of the spine. The ribs are attached to the spine, which means that when the spine twists, the ribs can move too. This twisting can cause the ribs to stick out to one side. The ribs will stick out on the side where the curve is.

Sacral Spine – (Sacrum) – The curved triangular bone at the base of the spine, consisting of five fused segments of the lower spine.

Sciatica – A lay term indicating pain along the course of a sciatic nerve, especially noted in the back of the thigh and below the knee.

Scoliometer – A painless and simple device used to measure trunk rotation.

Scoliosis – Lateral deviation of the normal vertical line of the spine which, when measured by x-ray, is greater than ten degrees. Scoliosis consists of a lateral curvature of the spine with rotation of the vertebrae within the curve. Rotation of the vertebrae also occurs which produces the rib cage and flank muscle asymmetry.

Scheuermann’s kyphosis: Scheuermann’s kyphosis is a condition that occurs during adolescence, where the front sections of the small individual bones in the spine (called vertebrae) grow slower than the back sections. As a result, these bones grow into the shape of a wedge. These wedge-shaped bones cant stack up in a straight line as usual, which causes an outward curve of the upper part of the spine.

Spinal Canal – The long canal between the vertebral bodies anteriorly and the lamina and spinous processes posteriorly through which the spinal cord passes. The spinal cord and nerve roots extend to the level of the second lumbar segment in adults. Below this level are numerous nerve roots from the spinal cord that resemble a horse’s tail and is referred to as such (cauda equina). The thick outer covering of the spinal cord is called the dura.

Spinal Fusion – A surgical procedure of stabilizing (permanently join to prevent motion) two or more vertebra by bone grafting. Can be done from the front (anterior), back (posterior), or as a staged procedure (first anterior and then posterior), usually with instrumentation.

Structural Curve – A segment of the spine that has fixed (nonflexible) lateral curvature.

Thoracic (Dorsal) Spine – Twelve spinal segments (T1-T12) incorporating the 12 ribs of the thorax. Other than a slight increase in size from top to bottom, they are fairly uniform in appearance.

Thoracic Curvature – Any spinal curvature in which the apex of the curve is between the second and eleventh thoracic vertebrae.

Thoracolumbar Curve – Any spinal curvature that has its apex at the twelfth thoracic or first lumbar vertebra.

Thoracolumbosacral Orthosis (TLSO) – A type of brace immobilizing the thoracic lumbar and sacral spine. This may be used to help stabilize/ prevent progression of scoliosis curve(s) while a child is growing, or to immobilize the spine after surgery.

Vertebra – One of the 33 bones of the spinal column. A cervical, thoracic, or lumbar vertebra has a cylindrically shaped body anteriorly and a neural arch posteriorly (composed primarily of the laminae and pedicles as well as the other structures in the posterior aspect of the vertebra) that protect the spinal cord. The plural of vertebra is vertebrae.

Vertebral Column – The flexible supporting column of vertebrae separated by discs and bound together by ligaments.


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