A bulging disk, also known as a contained spinal disorder, is a condition characterized by bulging of an intervertebral disc towards the spinal canal. This condition primarily occurs either due to old age or from trauma to the spinal column.

A bulging disk usually occurs in the spinal or lumbar region, lower back, and in few cases, the neck. It commonly occurs as the human body ages, and with the increase in age, degeneration of the intervertebral disks occur. Disks are soft spongy material that are present between each vertebra of the spinal column to help cushion them. It's round in shape and looks similar to a doughnut. When the disc moves out of its normal location or radius, a case of bulging disk is said to occur. Almost 90% of all cases occur in the lower back as that is the most stress bearing part of the spine. Hence, all kinds of movements and weight bearing activities have a direct bearing on the small of your back.

To understand the phenomenon of a bulging disk, we have to understand the anatomy and physiology of an intervertebral disc.

Intervertebral Disc
The spinal cord is encased in the spine that is made up of intervertebral discs and vertebrae whose primary function is to support the body's weight. Each vertebra of a spine contains an attached intervertebral disc that is made up of a tough exterior (annulus fibrosus) that helps keep the soft interior (nucleus pulposus) in place. The stress of everyday physical activity is transferred to these discs that act as shock absorbers to any kind of impact, thus protecting the spinal cord from injury. A healthy disc is made of a particular type of tissue that is negatively charged and is hydrophilic in nature. Its affinity to water is what helps keep it flexible, and the inside jelly-like. This water content enables the disc to remain spongy in nature. Excessive pressure or injury can be harmful for the structure of the outer ring of the ligament covering the nucleus pulposus.

Pathology and Mechanism
Due to aging, the scars received by the annulus over time, lead to small cracks. When the cracks become too big to hold the jelly like pulposus inside, it gives way. This causes the nucleus pulposus to start bulging from its place, which gives rise to the condition. So the cushion effect diminishes and the spine loses its ability to absorb stress.

The other side effect that a bulging disk causes is that the space between two intervertebral discs decreases, even collapses, which results in the movement of two adjoining discs to come closer. Because of this movement, there is a considerable shift in the location of facet joints at the back of spine. Bone spurs form due to the activities of osteophytes which begin to accumulate around the disc spaces and facet joints. This spurring process is a natural response by the spine to reduce the excessive motion of that typical segment of the spine.

Pathologically, this condition is known as a Bulging Disc or a herniated disc. Now a bulging disk normally gives rise to pain if the bulge presses against a nerve in the spinal cord. It may also allow the pain to radiate to surrounding parts of the body because the entire nerve will carry the impulse. Hence, it's not uncommon to find the shoulders or even the hands in pain. However, when there is no nerve for it to come in contact with, it may remain asymptomatic and will only show up on a routine MRI. The pain that is emitted is also caused by inflammation because the body will tend to increase the blood supply to the affected nerve in the hope of healing it.

Symptoms
The symptoms of a bulging disc usually depend upon the precise location of the affected intervertebral disc in the spine. A person may suffer from pain and discomfort in their legs and hips if a disc at the lower back is affected, while others may suffer symptoms such as pain in the arms if the affected disc is located near the shoulder region in the upper back. The symptoms from this degenerating disc include discogenic pain. And as explained above, some cases also go without displaying any symptoms.

Diagnosis
Magnetic resonance imaging (MRI), CT scans and X-rays are certain imaging tests that confirm the presence of a bulging disk. The diagnosis is made only after taking the complete case history of the patient. MRI and CT Scans help by giving detailed images of soft tissues and bony structures respectively. X-rays can be used to check the prognosis, it is rarely used for diagnosing herniated discs these days. There also are advanced nerve-related tests like Discography, Myelogram, Nerve Root Block and Electromyogram and Nerve Conduction Test that could be employed for an accurate diagnosis.

Treatment

a) Conservative Treatment
According to assessment of the severity of the pain, treatment is decided. Some problems need immediate medical attention while others do require plenty of rest with medication like anti-inflammatories, analgesics, and cortisones. In some cases, if protrusion is much more into the spinal canal, then surgery is required. The treatment is aimed at making the patient comfortable as quickly as possible, by getting him/her back to a normal state in a time bound carefully designed rehabilitation program to reduce further wear and tear of the disc.

b) Rest
Rest plays the most important role in the treatment of a bulging disc. In most of the cases, a complete, sound rest is what your body is craving for. It is helpful to reduce the stress and pressure off your spine. Sometimes, placing a pillow under the knees can help a lot. Although rest is an important parameter avoid prolonged bed rest, try to return to your normal activities gradually. Rest combined with a small amount of recommended exercises can do wonders.

c) Physical Therapy
In most cases, physical therapy proves to be of immense help in a rehabilitation program. Workout with an expert physical therapist helps in reducing inflammation and pain, improving and rebuilding your strength, and returning to normal activities with greater ease. A well-rounded physical therapy program is aimed at controlling symptoms, and practicing mobility and safe exercises. For a patient suffering from back pain, gradual physical exercises is the best way to combat the pain. It also teaches you to maintain a correct posture while sitting at a desk or while walking, and how if the demand arises, to distribute weight over your entire body instead of concentrating it only on your spine.

d) Epidural Steroid Injection (ESI)
Used as pain killers, they are of great help to control inflammation. They act as a local anesthesia to block sensation in the back.

In Conclusion
Therapy goes a long way in treating this condition and should be an essential part of your routine, coupled with a good and nutritious diet. Keep in mind that the body will try its best to heal the affected area, however, you need to help it achieve that. Your blood should be able to have enough nutrients in it for it to mend the area. Practicing Yoga is a good treatment option because it contains a few powerful asanas which helps correct posture and align the back and the spinal cord in place.

Although a bulging disc is commonly seen in the elderly population, not all old people will experience the pain associated with it. Only when the disc extends itself towards the nerves of the spinal canal will the pain make itself present. Hence, it's very important to get yourself checked every couple of years to spot the condition early and arrest it then and there.