Also known as: Crooked Spine


The spinal column has natural curves which gives roundness to shoulders/chest (thoracic kyphosis) and makes our lower back curve slightly inwards (lumbar lordosis) when viewed from the side. When seen from the back, the spine should normally be straight with the head in line with the middle of the pelvis. However, some people may have curves from side to side and this condition of sideward bend in the spine is called scoliosis. The terminology is derived from Greek word skolios meaning crooked. The spine can look either like an ‘S’ or ‘C’.

The prevalence of scoliosis measuring more than 10 degrees is 2 to 3 per cent, but only 3 in 1,000 (0.3 per cent) have curves more than 20 degrees. While the incidence is roughly equal in boys and girls for small curves, girls have 10 times the risk of developing curves more than 30 degrees.


Medical text written December 2010 by Mr NS Harshavardhana, Clinical Spinal Fellow and Mr CI Adams, Consultant Spinal Surgeon, Scottish National Spinal Deformity Service, Edinburgh, UK. Also reviewed by Mr DE Porter, Consultant Orthopaedic Surgeon, Royal Infirmary of Edinburgh, Edinburgh and the Royal Hospital for Sick Children, Edinburgh, UK.

What are the symptoms?

Scoliosis is a descriptive term and not a diagnosis. It is a complex three-dimensional deformity of the spine and is often accompanied by bending and twisting of bones resulting in prominence of the ribs (rib hump) with uneven shoulders and asymmetry in size or location of breasts. There may also be waistline asymmetry/flank fullness with trunkal shift to one side. Children and adolescents with scoliosis are often pain-free, although pain may require further investigation. It is usually detected incidentally by parents, friends, PE instructor or ballet teacher. It is also commonly noticed in summer holidays when the prominent shoulder blade or uneven waistline is obvious in swimsuits.

What are the causes?

In 80 per cent of instances no specific cause is found and such cases are termed as idiopathic. The most common type of scoliosis is the one that develops during adolescence (10-14 years of age) and hence termed adolescent idiopathic scoliosis (AIS). AIS constitutes 70 per cent of all scoliosis cases. In a small proportion of cases, scoliosis could be due to birth defects (congenital scoliosis), muscle imbalance or neurological causes (neuro-muscular scoliosis) and as a part of syndrome (i.e. neurofibromatosis or Marfan syndrome).

A total of 30 per cent of AIS patients have a family history of scoliosis and there seems to be a genetic connection. Research is ongoing in this area and there are many genes associated with scoliosis. It is also likely that these genes may be helpful in detecting and determining the risk of progression of the curve with growth. There is no definite inheritance pattern in scoliosis and it could best be described as being multi-factorial.

How is it diagnosed?

Initial assessment and diagnosis is usually done by a specialist who does a detailed examination of the back and nervous system. Standing X-rays in two planes (two different types of view: from the front (AP) and the sides (lateral)) from neck to pelvis are obtained and angle of curve is measured (Cobb angle). Some specialist centres may also get further tests at this stage such as an ISIS scan. An ISIS scan is a technique that allows the assessment of the surface shape of the back in three dimensions. Magnetic resonance imaging and (MRI) and computed tomography (CT) scans may also be required.

How is it treated?

The treatment options for scoliosis fall into three main categories:

This is for small curves (less than 20 to 25 degrees) especially in growing years (under 10 years old), or for moderate curves (less than 40 to 45 degrees) when growth is completed and involves monitoring the curve and any associated problems carefully. In adults with small/moderate curves, physical therapy and exercises for those patients who have mild symptoms is recommended initially.

This is for curves between 25 and 45 degrees in growing children to prevent worsening of the curve with growth. The brace acts as an external scaffold directing the spine in the desired direction as the spinal column lengthens. Braces cannot correct curves.

This is reserved for curves which are generally greater than 50 degrees in adolescents and adults. Surgery can be performed for moderate curves if it is cosmetically unacceptable or for associated symptoms (pain or weakness). The goals of surgical treatment are to obtain curve correction and correct asymmetry and rib hump. This is usually achieved by placing metal implants (screws/hooks and rods), which hold the spine in corrected position until fusion (knitting of the spinal elements together) occurs.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
There is no definite inheritance pattern in most types of scoliosis and it could best be described as being multi-factorial; any pattern of inheritance will depend upon the disorder concerned.

Prenatal diagnosis
None, except where specific conditions are concerned, for example, in spina bifida where amniocentesis at 16 weeks is used. Ultrasound scanning can also identify spinal cord and vertebral defects.

Is there support?

Scoliosis Association (UK) (SAUK)

Helpline: 020 8964 1166 

The Association is a Registered Charity in England and Wales No. 285290. It provides information and support to people with scoliosis and other spinal conditions including kyphosis and lordosis. Members have access to the scoliosis contacts network, the online forum and local support through Regional Representatives.

Group details last updated December 2014.

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