The occipital artery (Latin: arteria occipitalis) is one of the posterior branches of the external carotid artery that arises below the posterior belly of the digastric muscle. The occipital artery supplies blood to the back of the scalp, sternocleidomastoid, trapezius, deep muscles of the back, and dura mater of the posterior cranial fossa.
After it emerges, the occipital artery passes posteriorly to the level of the posterior belly of the digastric muscle. Then it crosses the carotid artery, the internal jugular vein, the hypoglossal, vagus, and accessory nerves. The occipital artery ascends between the transverse process of the atlas (C1) and the mastoid process of the temporal bone, reaching the lateral border of the rectus capitis lateralis muscle. Then the artery passes in the occipital groove of the temporal bone being covered by the sternocleidomastoid, splenius capitis, longissimus capitis, and digastric muscles and resting upon the obliquus superior, rectus capitis, semispinalis capitis muscles. The occipital artery then changes its course, turning upwards to penetrate the deep cervical fascia. It then ascends in the dense superficial fascia of the scalp, where it divides into many branches that supply the skin of the back of the scalp.
The occipital artery has two main branches: the upper and the lower branch.
The upper branch arises as the occipital artery passes the accessory nerve, then it descends posteriorly to enter the deep surface of the sternocleidomastoid along with the accessory nerve.
The lower branch of the occipital artery arises near the origin of the occipital artery, descends backward, enters the sternocleidomastoid, and forms anastomoses with the sternocleidomastoid branch of the superior thyroid artery.
The lower branch also gives off a mastoid branch that enters the posterior cranial fossa via the mastoid foramen to supply the dura mater.