Rib Hump: A Sign of Scoliosis

Why a rib hump forms

Scoliosis is not just a sideways bend. The vertebrae also rotate around the spine's long axis. Because the ribs attach to the vertebrae, they rotate with them. On the outside (convex side) of a curve in the chest area, the ribs swing backward and create the hump. On the opposite side, the ribs at the front may become more prominent.

A rib hump points to a curve in the thoracic (chest) spine. A curve in the lower back creates a similar bulge of the muscles beside the spine, called a lumbar prominence.

Causes

• Adolescent idiopathic scoliosis: the commonest cause. It appears during the growth spurt, usually between 10 and 15 years old. Small curves are about as common in boys as girls, but curves that progress and need treatment are much more common in girls. The cause is unknown but it runs in families.
• Congenital scoliosis: vertebrae formed abnormally before birth.
• Neuromuscular scoliosis: in conditions such as cerebral palsy, spina bifida and muscular dystrophy.
• Syndromes: Marfan syndrome, neurofibromatosis and Ehlers-Danlos syndrome.
• Degenerative scoliosis: in older adults, from disc and joint wear.

Other signs that come with a rib hump

• one shoulder higher than the other (uneven shoulders)
• one shoulder blade sticking out more
• a deeper waist crease on one side
• clothes hanging unevenly, or one trouser leg seeming longer
• the body leaning to one side, one of several postural problems scoliosis can cause
• head not centered over the pelvis

Most adolescent scoliosis is painless. Significant back pain needs a doctor's assessment to rule out other problems.

Rib hump vs other back bumps

How a rib hump is assessed

Adams forward bend test

The child bends forward with feet together, knees straight and arms hanging. The examiner looks along the back from behind and in front. A hump on one side suggests scoliosis.

Scoliometer

A small device placed across the back measures the angle of trunk rotation. A reading of about 5 to 7 degrees or more usually prompts an X-ray.

X-rays

Standing X-rays of the whole spine measure the Cobb angle, the size of the curve. Scoliosis is defined as a curve of 10 degrees or more. X-rays also show how much growth remains, which predicts the risk of worsening. An MRI is ordered for unusual curve patterns, pain, neurological signs or very young children.

Treatment

The aim is to prevent progression during growth. The rib hump itself improves somewhat only when the underlying curve is treated.

• Observation: curves under about 20 to 25 degrees in growing children are checked every 4 to 12 months with exams and X-rays.
• Bracing: for growing children with curves of about 25 to 40 degrees. A rigid brace worn 13 to 20 hours a day reduces the chance that the curve will reach the surgical range. It holds the curve but does not usually reduce an existing rib hump much.
• Scoliosis-specific exercises: such as Schroth-based programs can help posture and may help small curves, often alongside bracing.
• Surgery: spinal fusion with rods and screws for curves usually over 45 to 50 degrees in growing children, or that continue to progress. It straightens and stabilizes the spine and usually reduces the rib hump. Some surgeons also shorten the ribs (thoracoplasty) for a large remaining hump. Vertebral body tethering is an option for some still-growing children.

After growth stops, curves under about 30 degrees rarely progress. Larger curves can slowly increase in adulthood.

Frequently asked questions

Is a rib hump always scoliosis?

Usually, but not always. Mild asymmetry can come from muscle development, posture or a leg length difference. A hump that is more obvious when bending forward strongly suggests scoliosis and should be checked with a scoliometer or X-ray.

Can a rib hump go away?

A rib hump does not go away on its own because it reflects rotation of the spine. Bracing stops it worsening in most children. Spinal fusion surgery straightens the spine and usually reduces the hump significantly.

Is a rib hump painful?

Most rib humps in teenagers are painless. Adults with scoliosis may have back pain from muscle strain or degeneration. A painful curve in a child, especially with night pain or neurological symptoms, needs further tests to rule out other causes.

Can exercise fix a rib hump?

Exercise cannot reverse the bony rotation that causes a rib hump. Scoliosis-specific exercise programs can improve posture, strength and appearance somewhat, and may help small curves, but they do not replace bracing for curves in the treatment range.

At what age should children be checked for scoliosis?

Many pediatric and orthopedic societies support screening around ages 10 to 12 for girls and 13 to 14 for boys, when growth spurts happen. Any noticeable rib hump, uneven shoulders or waist should be checked at any age.