Video: Suboccipital muscles

Hello, everyone! Welcome to another Kenhub anatomy tutorial. In this tutorial, we’re going to be talking about a group of four muscles known as the suboccipital muscles.

The suboccipital muscles are a group of muscles that are located inferior to the occipital bone of the skull. In this posterior view of the head and neck, you can see the suboccipital muscles located at the base of the skull.

There are four pairs of suboccipital muscles, one set on either side of the body. The four pairs can be roughly split into two groups, the first of which are known as the rectus capitis posterior muscles. The rectus capitis posterior has a minor and a major muscle.

The second group is the obliquus capitis muscles. In this group of muscles, there’s an obliquus capitis inferior muscle and an obliquus capitis superior muscle.

Let’s begin by talking about the rectus capitis posterior group, starting with the minor muscle. The rectus capitis posterior minor muscle arises from the posterior tubercle of the atlas, otherwise known as the first cervical vertebra. The muscle attaches to the tubercle via a narrow, pointed tendon.

The muscle then fans out in a superolateral direction to attach to the medial part of the inferior nuchal line of the occipital bone.

The rectus capitis posterior minor muscle functions to extend the head bilaterally at the atlantooccipital joint. It therefore has an important role in posture and stabilizing the head during standing and other movements.

The rectus capitis posterior major is a triangular shaped muscle, arising from the spinous process of the axis, otherwise known as the second cervical vertebra. It arises deep to obliquus capitis superior and semispinalis capitis muscles.

Like the rectus capitis posterior minor muscle, the muscle then passes superolaterally, skipping the first cervical vertebra, to insert via a broader attachment on the lateral part of the inferior nuchal line.

Bilaterally, the rectus capitis posterior major muscle also functions to extend the head at the atlantooccipital joint. Unilaterally, along with the obliquus capitis inferior and splenius capitis, it functions to rotate the head at the atlantoaxial joint to the ipsilateral side. It’s also an important postural muscle, helping to stabilize the atlantoaxial joint during movement.

Let’s now talk about the next muscle group, the obliquus capitis muscles, starting with the inferior one. The obliquus capitis inferior muscle is the larger of the two oblique muscles of the neck. And it arises from the lateral surface of the spinous process of the axis.

With regards to its insertion, unlike the other suboccipital muscles, the obliquus capitis inferior muscle does not insert onto the skull. Instead, it passes in a superolateral direction to insert onto the inferoposterior aspect of the transverse process of the atlas.

Like the rectus capitis posterior major muscle, bilaterally the obliquus capitis inferior functions to extend the head at the atlantooccipital joint, while unilaterally it rotates the head towards the ipsilateral side at the atlantoaxial joint. Like the other suboccipital muscles, the muscle plays an important role in posture, working alongside the other suboccipital muscles to stabilize the atlantoaxial joint. It’s also a strong rotator of the neck.

Let’s now look at our final suboccipital muscle. As you can see, the obliquus capitis superior is smaller than the obliquus capitis inferior. It originates from the superior surface of the transverse process of the atlas. As it ascends upwards, it fans out and broadens to insert between the superior and inferior nuchal lines on the external surface of the occipital bone. The insertion is lateral to the semispinalis capitis and anterolateral to the rectus capitis posterior major.

Bilaterally, the obliquus capitis superior functions to extend the head at the atlantooccipital joint. Unilaterally, it flexes the head laterally to the ipsilateral side. Again it has an important role in posture, stabilizing the atlantooccipital joint during head movements.

Great! We’ve covered the origins, insertions, and functions of the suboccipital muscles. Let’s quickly talk about the blood supply and innervation.

The suboccipital muscles receive their blood supply from the vertebral artery as well as from the deep descending branches of the occipital artery. They receive their nerve supply from the suboccipital nerve, otherwise known as the posterior ramus of the first cervical nerve.

And that’s it for the suboccipital muscles! Thanks for watching, and see you next time!