Learning objective:
Understand the anatomy, attachments, actions, and innervation of the suboccipital muscles, and recognize the boundaries and contents of the suboccipital triangle.
The suboccipital muscles are a group of four deep muscles located beneath the occipital bone, in the suboccipital compartment of the neck. They lie deep to the sternocleidomastoid, trapezius, splenius, and semispinalis muscles.
These muscles are collectively responsible for extension and rotation of the head and are all innervated by the suboccipital nerve (posterior ramus of C1).
Overview of suboccipital muscles
| Muscle | Attachments | Actions | Innervation |
|---|---|---|---|
| Rectus capitis posterior major | Origin: Spinous process of C2 (axis) Insertion: Lateral part of inferior nuchal line of occipital bone |
Extension & rotation of the head | Suboccipital nerve (C1 posterior ramus) |
| Rectus capitis posterior minor | Origin: Posterior tubercle of C1 Insertion: Medial part of inferior nuchal line |
Extension of the head | Suboccipital nerve (C1 posterior ramus) |
| Obliquus capitis inferior | Origin: Spinous process of C2 Insertion: Transverse process of C1 |
Extension & rotation of the head | Suboccipital nerve (C1 posterior ramus) |
| Obliquus capitis superior | Origin: Transverse process of C1 Insertion: Occipital bone (between superior & inferior nuchal lines) |
Extension of the head | Suboccipital nerve (C1 posterior ramus) |
Tip: The rectus capitis posterior minor has a connective tissue bridge to the dura mater, which may contribute to cervicogenic headaches.
Suboccipital triangle
The suboccipital triangle is a clinically important landmark for locating the vertebral artery and performing certain surgical procedures.
| Border / Structure | Description |
|---|---|
| Superomedial | Rectus capitis posterior major |
| Superolateral | Obliquus capitis superior |
| Inferior | Obliquus capitis inferior |
| Floor | Posterior atlanto-occipital membrane & posterior arch of C1 (atlas) |
| Roof | Semispinalis capitis |
| Contents | Vertebral artery, suboccipital venous plexus, suboccipital nerve |
Visual cue: Imagine the triangle as a roofed compartment with a “hidden artery” inside—the vertebral artery.
Clinical relevance
- The suboccipital muscles and triangle are key in posterior neck surgeries.
- Injury to the vertebral artery during procedures here can lead to serious complications.
- Dysfunction or spasm of these muscles may contribute to headache syndromes.
