The common erector spinae has insertions at the individual spinal processes, transverse spinal processes and supraspinal ligaments across the proximal lumbar and lower thoracic vertebra.
Contrary to common belief, the core is not a single muscle or organ, but comprises pelvic floor muscles, external obliques, internal obliques, rectus abdominus, multifidus, erectorspinae and transverse abdominus (TVA).