Suboccipital Region Anatomy: Muscles, Triangle, and Innervation

Overview

In this Osmosis video, the suboccipital region is presented as more than the back of the head. A pyramid-shaped muscle compartment sits just below the external occipital protuberance, housing four small muscles that help stabilize and move the head at the atlas and axis joints.

The video then introduces the suboccipital triangle boundaries and describes the key vessels and nerves inside the region, including the vertebral artery and the suboccipital nerve.

Key Nerves

The nerves involved include the suboccipital nerve, greater occipital nerve, lesser occipital nerve, and the posterior rami of C3-C7, which collectively provide innervation to the muscles and skin of the posterior neck area.

Takeaways

• Four suboccipital muscles: rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior, obliquus capitis inferior
• The suboccipital triangle contains the vertebral artery and suboccipital nerve
• Skin innervation comes from greater occipital, lesser occipital nerves, and posterior rami

Suboccipital Region Overview

The Osmosis video explains that the suboccipital region is more than just the posterior head area. It is a pyramid-shaped muscle compartment located inferior to the external occipital protuberance and deep to the upper cervical muscles. Within this compact space lie four small paired muscles that primarily maintain head posture but also participate in extension, lateral flexion, and rotation of the atlantoaxial joints.

"The suboccipital triangle houses the vertebral artery and the suboccipital nerve." - Osmosis

Muscles and the Suboccipital Triangle

The four muscles lie deep to the semispinalis capitis: rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior, and obliquus capitis inferior. Three of these form the boundaries of the suboccipital triangle: rectus capitis posterior major forms the superomedial boundary, obliquus capitis superior forms the superolateral boundary, and obliquus capitis inferior forms the inferolateral boundary. The floor is the posterior atlantooccipital membrane and the posterior arch of the atlas, while the roof is the semispinalis capitis. The vertebral artery and the suboccipital nerve occupy the central region of this triangle.

"The rectus capitis posterior major, obliquus capitis superior, and obliquus capitis inferior form the boundaries of the suboccipital triangle." - Osmosis

Nerves and Skin Innervation in the Posterior Cervical Region

Innervation in this area includes the suboccipital nerve, which is the posterior ramus of C1 and travels with the vertebral artery in the region. It innervates the suboccipital muscles but not the overlying skin. The greater occipital nerve (posterior ramus of C2) supplies the skin of the posterior scalp, while the lesser occipital nerve (C2-C3) supplies the skin of the superior posterolateral neck behind the external ear. The posterior rami of C3-C7 innervate the intrinsic back muscles and the skin adjacent to the vertebral column, with the rest of the back supplied segmentally by thoracic and lumbar posterior rami.

"The suboccipital nerve innervates the suboccipital muscles, but not the overlying skin." - Osmosis

Recap and Quick Quiz

The video ends with a quick quiz reinforcing the four suboccipital muscles and the nerves involved in the suboccipital and posterior cervical regions, followed by a recap of the triangle's contents and boundaries.