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Other Terms: Arteria occipitalis, Artère occipitale
The occipital artery is a very large artery. It is one of the posterior branches of the external carotid artery. It arises opposite the facial artery, near the lower border of the posterior belly of the digastric muscle. Along the digastric muscle, it runs to the interval between the mastoid process of the temporal bone and the transverse process of the atlas. It reaches the groove on the under surface of the mastoid portion of the temporal bone. At its origin, it is crossed by the hypoglossal nerve. On its way to the mastoid process it crosses the internal carotid artery, the internal jugular vein, and the pneumogastric hypoglossal and spinal accessory nerves. It passes beneath the lower portion of the parotid gland. It runs horizontally backward through the occipital groove of the temporal bone, covered by all the muscles attached to the mastoid process: the sternocleidomastoid, splenius capitis, and the posterior belly of the digastric muscle. It lies superior upon the oblique and semispinalis capitis muscle. The artery pierces the trapezius muscle close to the superior curved line of the occipital bone, ascends, and divides into branches. As it pierces the trapezius muscle and ramifies in the superficial fascia of the scalp. It is divided by the sternocleidomastoid muscle into three parts. The first portion is covered only by skin and fascia except where it is overlapped by the posterior belly of the digastric muscle, the parotid gland, and the temporomaxillary vein. It is crossed by the hypoglossal nerve. Behind it is the internal carotid artery, the hypoglossal, and the pneumogastric nerve, the internal jugular vein, and the spinal accessory nerve. The second portion dips deeply under the digastric muscle between the mastoid process of the temporal bone and the transverse process of the atlas. It is covered by the muscles attached to the mastoid process and lies against the rectus capitis lateralis, which separates it from the vertebral artery, the mastoid portion of the temporal bone while passing though the occipital groove, and against the insertion of the superior oblique muscle. The third portion emerges from beneath the posterior border of the sternocleidomastoid and splenius muscles. It lies upon the semispinalis capitis in the triangular interval between the sternocleidomastoid and the trapezius and pierces the trapezius muscle about midway between the mastoid process and the external occipital protuberance to become subcutaneous and pass upward in the superficial fascia of the scalp. It is accompanied by the great occipital nerve. The branches given off from the occipital artery are the muscular, superior sternocleidomastoid, auricular, posterior meningeal, mastoid, princeps cervicis, communicating, and terminal. The muscular branches supply the digastric, stylohyoid, splenius, trachelomastoid, trapezius, recti, superior and inferior oblique and occipitalis muscles. The superior sternocleidomastoid artery enters the sternocleidomastoid muscle with the spinal accessory nerve. It arises from the first portion of the occipital artery, and passes downward and backward over the hypoglossal nerve to enter the sternocleidomastoid muscle. The auricular branch supplies the back of the pinna. At times, it is large and can take the place of the posterior auricular artery. It may send a branch to the dura mater through the mastoid foramen. The posterior meningeal branches ascend along the internal jugular vein and enter the cranial cavity through the jugular foramen to supply the dura mater of the posterior cranial fossa. The mastoid branch is a small vessel which traverses the mastoid foramen to supply the diploe, the walls of the lateral sinus, the dura mater, and the mastoid air cells. The princeps cervicis artery is the largest branch of the occipital artery. It runs down the back of the neck between the splenius and semispinalis capitis muscle. It divides into a superficial and a deep branch. The superficial branch pierces the splenius and runs between it and the trapezius, supplying these muscles. It anastomoses with the superficial cervical artery, one of the terminal branches of the transversalis colli. The deep branch descends between the semispinalis capitis and semispinalis colli, supplying these muscles. It anastomoses with branches of the vertebral and with the deep cervical branch of the superior intercostal artery. Communicating branches run between the recti and the superior and inferior oblique muscles to anastomose with branches of the vertebral artery. The terminal branches pass laterally and mesially upward in the superficial fascia of the occipital region of the scalp to supply the scalp and pericranium. They are known as external and internal. They anastomose with the occipital artery of the opposite side, the posterior auricular and the superficial temporal artery.