**3. Overview of musculoskeletal conditions**

Mechanical back pain: Often called back strain or musculoskeletal back pain. The etiology encompasses numerous causes, but the diagnosis excludes anatomical sources of pain such as a herniated disc or spondylosis. Common sources are strain of the paraspinal muscles (the muscles along the spine), strain of ligaments of the spine, or generative facet joint disease (the joints between the bones of the spine) [11].

Sciatica: This condition is usually caused by irritation of a nerve root of the sciatic nerve, often from compression by a disc or degenerative disease. Pain radiates into the buttocks, back of the thigh, and often into the calf or foot [12].

Radiculopathy: Dysfunction of the nerve root by any cause. Symptoms include weakness, pain (sciatica), numbness, paresthesias (tingling), or a combination thereof [13].

Herniated disc: Also called disc rupture, disc prolapse, or herniated nucleus pulposus (the gelatinous inner core of the disc). The annulus fibrosis is the outer layer of the disc, which is the strongest portion of the disc and provides the strength to prevent disc herniations. With age or injury, the wall of the spinal discs can become damaged and the wall of the disc can weaken and protrude. Disc pain is often felt as a deep ache in sacroiliac can be in the same location and feel the same [14].

Spinal Stenosis: This is a narrowing of the spinal canal, typically in the neck (cervical stenosis) or lower back (lumbar stenosis). The narrowing is called spondylosis. The etiology can vary (degenerative, trauma, congenital), but the most common spondylosis is a degenerative disorder, occurring with age. The hallmark of lumbar stenosis is pain in the back and legs that is aggravated by standing or walking and relieved by sitting or forward bending [15].

Myofascial pain: Refers to soft-tissue pain usually arising from trauma, repetitive activities, or poor posture. It is usually associated with muscle spasm. Patients may complain of pain in the neck region or pain across the top of the shoulders and sometimes sleep difficulties or headaches [16].

Scoliosis: This condition is an abnormal curvature of the spine. It has many causes, but the most common type is adolescent idiopathic scoliosis. Females are affected 8 times as frequently as males. In general, most forms of scoliosis are not specifically painful but may depend on the degree of curvature of the spine and/or the presence of degenerative spinal changes. Patients with a curvature.30 degrees may have more back pain during their lifetime than a person with a straight spine [17].

Fibromyalgia: Literally means muscle/soft-tissue pain. Patients complain of generalized myalgia, stiffness, or soreness. The pain is disseminated and occurs in different areas of the body at different times. The pain can increase with menstrual cycle or with sudden weather changes. A key diagnostic feature is concurrent fatigue and sleep disorder, with disruption of stage 4 sleep (an alpha EEG anomaly). Pain appears to improve with medications, physical exercise, and efforts to promote normal sleep

patterns. Patients may have neurological disturbances such as headaches, numbness, weakness, difficulty concentrating, and lightheadedness. As many as 50% of patients have clinical depression in their lifetime [18].
