Dissection and Detachment of Suboccipital Triangle Muscles. A, The suboccipital triangle is composed by the rectus capitis posterior major muscle, above and medially, by the superior oblique muscle above and laterally, and by the inferior oblique muscle below and laterally. B, Cadaverous specimen after the dissection and detachment of suboccipital triangle muscles, in order to show closely the neurovascular structures inside the triangle. We can find the terminal extradural vertebral artery, its muscle branches and first and second cervical neural root. (Images courtesy of E de Oliveira)