Ace Your Spinal Anatomy Exam 2026 – Dive Deep into the Backbone of Your Success!

The key idea is how the transversospinalis muscles differ in depth and how far their fibers span along the spine. The semispinalis is the most superficial of this group and has the longest reach, typically spanning about 4 to 6 vertebral segments from its transverse-process origin to the spinous-process insertion several levels above. In contrast, rotatores lie deepest and usually span only 1–2 segments, while multifidus sits between them, spanning roughly 2–4 segments. The rectus capitis posterior major is not part of the transversospinalis group at all. So the semispinalis best fits both criteria: it’s the most superficial among the transversospinalis muscles and it spans the greatest number of vertebral segments.