Anatomical Variation in a Deep Back Muscle and Possible Implications

Background: The longissimus thoracis muscle is a part of the erector spinae muscle group, originating from the thoracolumbar fascia, and inserting onto the transverse processes of the first through twelfth thoracic spinevertebrae. The multifidus muscle originates from the posterior superior iliac spine (PSIS) and inserts into on the spinous processes; . iIt is involved in extension and stabilization of the vertebrae in localized movements. Dysfunctions of these muscles are often associated with low back pain, a common complaint among U.S. patients. Case Presentation: This case study describes a novel anatomical variation in the musculature of the deep back discovered during a routine dissection of a 72-year-old female cadaver. The variation identified in this subject is located unilaterally on the right side, from the PSIS, and ends at the transverse process of the third lumbar spinevertebrae. Conclusions: Based on our literature review, we have concluded that the variation is an atypical deep back muscle. Future studies could examine the effects of these variants, and their implication, in somatic and physiological dysfunctions, such as scoliosis.