The occipitalis is a muscle located at the back of the head (occiput) that works with the frontalis muscle to raise the eyebrows and wrinkle the forehead.
Understanding the Occipitalis Muscle
The occipitalis muscle, part of the occipitofrontalis muscle, plays a crucial role in facial expression. Here's a breakdown:
- Location: It resides at the posterior part of the scalp, covering the occipital bone.
- Origin: It originates from the highest nuchal line on the occipital bone and the mastoid part of the temporal bone.
- Insertion: The occipitalis inserts into the galea aponeurotica, a broad sheet of fibrous tissue connecting it to the frontalis muscle.
- Function: While the occipitalis itself doesn't directly move the scalp or eyebrows, it tenses and retracts the scalp, allowing the frontalis muscle to raise the eyebrows and wrinkle the forehead. It essentially anchors the galea aponeurotica, providing a stable base for the frontalis to act upon.
- Innervation: The occipitalis muscle is innervated by the posterior auricular branch of the facial nerve (CN VII).
Occipitalis vs. Frontalis
The occipitalis and frontalis muscles work in tandem. The frontalis muscle is located in the forehead and is responsible for raising the eyebrows and wrinkling the forehead. The occipitalis muscle provides the anchor for the frontalis to pull against. Together, they create a range of facial expressions.
Clinical Significance
- Damage to the facial nerve can affect the function of the occipitalis muscle, leading to a loss of expression in the forehead region.
- Tension in the occipitalis muscle can contribute to tension headaches.
In summary, the occipitalis muscle, though not directly responsible for major movements, is vital for supporting facial expressions by anchoring the scalp and facilitating the action of the frontalis muscle.
