Idiopathic primary BSS is a late-onset myopathy with progressive muscular weakness that is detected on the spinal extensor muscles in elderly patients and is more predominant in females.[2] The pathogenesis of primary BSS is typically related to fibrosis and fatty infiltration of muscular tissues and to mitochondrial changes due to the aging process.[2] Specifically, weakening occurs in the paravertebral muscles of patients. These paravertebral muscles have a great influence over the walking stance and gait of a patient, so fatty infiltration and degradation of these muscle lead to the characteristics that easily define BSS, such as the anterior flexion of the back combined with an ability to keep upright with any kind of support (e.g., holding onto a table).[2]