Occipital artery

Origin and course

The occipital artery originates from the external carotid artery at approximately 2 centimeters above the bifurcation of the common carotid artery. After crossing the hypoglossal nerve, the occipital artery continues in a posterior superomedial direction, parallel and deep to the posterior belly of digastric muscle. On its way through the posterosuperior aspect of the carotid triangle, it passes anterior to the internal carotid artery, internal jugular vein, vagus and accessory nerves.

After crossing the lateral margin of the rectus capitis lateralis muscle, it reaches the skull where it passes in the shallow occipital groove of temporal bone (if running deep to the longissimus capitis muscle), medial to its mastoid process. It then pierces the deep cervical fascia between the trapezius and sternocleidomastoid muscles, along with the greater occipital nerve. When it reaches the scalp, it gives off several branches that travel across the surface of the occipitofrontalis muscle and anastomose with their contralateral counterparts.

Branches and supply

The occipital artery gives off several branches. They include:

• Sternocleidomastoid artery
• Descending branch/muscular branches
• Auricular branch
• Mastoid branch
• Occipital branches
• Meningeal branch

The initial branch arising from the occipital artery is the sternocleidomastoid artery. In the carotid triangle, this branch divides into two parts (upper and lower); alternatively, they can both arise directly from the occipital artery. The sternocleidomastoid branches descend posteriorly towards its namesake muscle.

The descending branch arises posterior to the posterior belly of the digastric muscle. While descending, it gives off several muscular branches to supply the posterior deep back muscles. These include the digastric, rectus capitis lateralis, stylohyoid, obliquus capitis inferior, obliquus capitis superior, rectus capitis posterior major, rectus capitis posterior minor, semispinalis capitis, splenius capitis and splenius cervicis muscles.

The auricular branch vascularizes the skin of the posterior aspect of the auricle, while the occipital branch mainly vascularizes the occipital belly of the occipitofrontalis muscle.

The occipital artery gives off two branches that supply the dura mater: meningeal and mastoid branches. The mastoid branch originates at the level of the insertion of the semispinalis capitis muscle and enters the posterior cranial fossa via the mastoid foramen. The meningeal branch variably reaches the meninges via the following skull apertures: jugular foramen, parietal foramen, foramen magnum, condylar canal.

Learn more about the superficial vessels of the head with our articles, videos, labeled diagrams and quizzes.

Anatomical variations

In most cases, the occipital artery arises directly from the external carotid artery. However, in some cases, it can originate from internal carotid, thyrocervical trunk, inferior thyroid and vertebral arteries. In approximately 15% of cases, the posterior auricular and occipital arteries form a mutual origin from the external carotid named the occipitoauricular trunk.

Instead of arising from the ascending pharyngeal artery, the posterior meningeal artery may arise from the occipital artery in 20% of cases.