Which muscle forms the roof of the suboccipital triangle?

• A. Rectus capitis posterior major
• B. Obliquus capitis superior
• C. Semispinalis capitis
• D. Splenius capitis

Answer: (C)

The roof of the suboccipital triangle is formed by the semispinalis capitis. This larger, more superficial muscle crosses the back of the neck and inserts on the occipital bone, overlying the deeper suboccipital muscles. As a result, it provides the covering over the triangle. The deeper muscles—rectus capitis posterior major medially, obliquus capitis superior forming the upper boundary, and obliquus capitis inferior forming the lower boundary—define the triangle itself, not its roof. Splenius capitis sits more superficially and laterally and does not cap the suboccipital triangle.