What Is Adam’s Forward Bend Test?
The adam’s forward bend test is used for detecting the presence of scoliosis (either functional or structural). There are two types of scoliosis functional and structural scoliosis.
This test is often performed at schools and doctor’s offices to detect the presence of scoliosis (either functional or structural).
Now let’s understand scoliosis and the difference between functional and structural scoliosis.
What is the Natural Curvature of Spine?
Scoliosis is an abnormal curvature of the spine. Now let’s first talk about the natural curvature of the spine.
The spine is typically made up of 24 individual bones called the vertebrae. These vertebrae align in a series to compose the spine. The vertebrae are separated by the intervertebral discs. The intervertebral disc allowed the spine to be flexible.
When viewed from the front and backside – the healthy spine appears straight.
The healthy spine makes an “S” like shape when viewed from the lateral side. How does this “S” shape structure form? Let’s discuss this.
In the natural curvature of the spine, there are two lordotic curves and two kyphotic curves. They alternate to make an “S” like shape when viewed from the lateral side. The lordotic curve means the spine curves inward, and the kyphotic means the spine curves outwards.
- The Lordotic Curve (inward curve) is present in the cervical and lumbar spine
- The kyphotic curve (outward curve) is present in the thoracic and sacral spine.
All these curves usually work together in coordination to keep the spine aligned over the hip and pelvis. Any imbalance in any of these natural curves can lead to deformities such as flatback syndrome, scoliosis, sway back, etc. The deformity will depend upon which curve is affected. For example,
Flatback syndrome – In this lumbar curve is affected. In this, the lumbar spine losses its natural curvature and becomes flat over time.
Swayback Posture – In this, the lumbar spine curves too far inward (extreme lordosis). This condition is known as swayback.
What is Scoliosis?
Scoliosis causes an abnormal side-to-side curve of the spine. In other words, you see a sideways shift of the spine (either to the left or to the right).
For a doctor to diagnose scoliosis, the cobb angle (a measure of curvature) must be greater than 10 degrees on X-rays. The Cobb angle is a measurement obtained via X-rays. It tells how far out of alignment a scoliotic spine is. The doctor may use the letter “C” or “S” to describe the curve.
As mentioned above, there are two types of scoliosis structural scoliosis and non-structural (functional scoliosis). Now let’s understand the difference between structural and non-structural (functional scoliosis).
Structural Scoliosis VS Non-structural (Functional scoliosis)
Structural scoliosis is considered true scoliosis as it is an actual change to the spine. It involves rotation of the spine in addition to the side-to-side curve of the spine of 10 degrees or more.
While non-structural scoliosis (functional scoliosis) is not considered true scoliosis as it may be present with the abnormal sideways curvature of the spine (either lift or right). But the most important thing it does not include the rotation of the spine, and the spine structure will still be normal.
The main reason why functional scoliosis is not considered true scoliosis is that it can be caused by a temporary cause such as muscle spasm, or chronic bad posture and any other irregularities in the body, such as leg-length discrepancy.
According to research, “If a person suffering from non-structural (functional) scoliosis, were to lay down or bend forward, the scoliosis curve would likely disappear while held in that position.” This thing we will test in the Adam Forward Bend Test.
Hence it is a strong indication that the patient does not have true scoliosis (abnormal sideways curvature of the spine but does not include rotation of the spine). It is more likely that their scoliosis is functional and related to muscle spasms, bad posture, or leg length discrepancy.
Cases of Non-structural scoliosis (functional scoliosis) that are caused by chronic bad posture can usually be treated by addressing postural issues. Stretches and exercises that encourage good posture can help.
While in cases of Functional scoliosis caused by leg length discrepancy. This can be treated by custom orthotics or insoles that can fix the leg length discrepancy. This relieves pressure off the spine and allows it to return to its normal curvature and alignment.
Now you understand the difference between structural and non-structural (functional) scoliosis. Now let’s study how the Adam forward bend test is used in detecting the presence of either structural or functional scoliosis.
Procedure for Performing Adam Forward Bend test
- Ask your patient to stand up straight, with arms flat at their side.
- The examiner then observes from behind and asks the patient to bend forward with their arms hanging down as if they were trying to touch their toes.
- Now, the examiner observes the contour of the posterior thorax.
- If the contour (shape) of the posterior thorax assumes the symmetrical form, then the underlying scoliosis is considered to be functional.
- Scoliosis is considered to be structural if the contour of the posterior thorax retains its asymmetry with the persistent rib hump.
Now you understand how to person the adam forward bend test. Now let’s understand the relationship between the rib hump and structural scoliosis.
Rib Hump And Scoliosis
Rib hump occurs due to asymmetry in the rib height. This asymmetry in the rib height causes one side of the rib cage to protrude more than the other. This is usually due to an abnormal spinal curvature present along the thoracic spine.
Size of Rib Hump – It’s not only how large the abnormal spinal curvature is that determines the size and presence of the rib hump but also the degree of rotation. In other words, the abnormal spinal curvature and the degree of rotation determine the size of the rib hump.
Causes of Rib Hump
The spinal cord runs through the spinal canal. It is located towards the back of your spine, not in the middle, as most people believe. Because of its flexibility, the spinal cord can move along the spine’s natural curvatures.
In a healthy spinal cord, with no adverse nerve tension, the spinal cord can stretch and bend to accommodate the body’s movement. Therefore, when fully flexed, the spinal cord has been known to elongate by 5 to 7 cms.
When nerve tension is present in the spinal cord, it effectively results in a shorter spinal cord. In other words, a shorter spinal cord results from nerve tension. When nerve tension and a shorter spinal cord are present, the spinal cord can’t stretch as far. The spinal cord will then take the shortest route possible to span the length of the spine as necessary. This means that the spinal cord is pulled even tighter.
When the tight spinal cord is pulled tighter, the spinal cord wants to escape that adverse spinal tension, and this it does by rotating in order to find the shortest path.
Now, as the spine travels through the spinal cord near the rear (back) of the spine, this rotation helps give the spinal cord a shorter route to travel. It’s this nerve and tension-driven rotation that results in the formation of the rib hump.
Now you understand the connection between the rotation of the spine and the formation of the rib hump. As explained above, structural scoliosis includes rotation of the spine. Now let’s study how adam forward bend test help in identifying structural scoliosis.
As explained above, while performing the adam forward bend test, if the contour of the posterior thorax retains its asymmetry with the persistent rib hump, the scoliosis is considered to be structural.
Now let’s understand how this happens?
A person with scoliosis may look normal from the back when they are standing. However, when bend forward at a 90-degree angle, as in Adam’s forward bend test, the spinal cord becomes shorter and tighter due to nerve tension. This is where the vertebrae (bones of the spine) rotate to provide a shorter path. The rotation causes the rib cage to distort, and a rib hump is more visible and identifiable as a scoliosis indicator.