Anatomical Course and Location
The occipital artery arises from the posterior aspect of the external carotid artery, at the same level as the a. facialis. From its origin, it:
- courses posteriorly along the posterior belly of the digastric muscle (m. digastricus);
- passes approximately midway between the external occipital protuberance and the mastoid process;
- pierces the trapezius muscle;
- branches superficially to the epicranius muscle (m. epicranius).
Topographically, the vessel runs in an upward direction beneath the subcutaneous fat layer and the occipital belly of the m. occipitofrontalis, running in close proximity to the greater occipital nerve.
Branches of the Occipital Artery
- Sternocleidomastoid branches (rr. sternocleidomastoidei) — arise directly from the occipital artery or the external carotid artery, supply the sternocleidomastoid muscle, and anastomose within its substance with branches of the subclavian artery;
- Mastoid branch (r. mastoideus) — passes through the foramen mastoideum to supply the dura mater;
- Auricular branch (r. auricularis) — supplies the posterior surface of the auricle;
- Occipital branches (rr. occipitales) — terminal branches supplying the skin and muscles of the occipital region;
- Meningeal branch (r. meningeus) — enters the cranium via the foramen parietale.
Anastomoses and Clinical Significance
The occipital artery anastomoses with branches of the ophthalmic artery and the superficial temporal artery. Specifically, the parietal branch of the superficial temporal artery anastomoses with the occipital artery.
Among the branches of the external carotid artery, the occipital artery is one of the most critical vessels participating in anastomoses between the external carotid and vertebral artery systems supplying the cervical and occipital musculature. This enables it to compensate for blood flow:
- in proximal occlusion of the vertebral artery — blood supply is compensated via the deep cervical branches of the occipital artery;
- in occlusion of the common carotid artery or proximal occlusion of the internal carotid artery — blood reaches the carotid system via the occipital artery through muscular branches of the vertebral artery.
Supply to Neighboring Structures
The occipital artery contributes to the blood supply of the digastric muscle alongside the a. submentalis. It is also classified among the posterior group of external carotid branches supplying the scalp and neck muscles, a group that includes the a. auricularis posterior, which supplies the auricle and the mastoid region.