The vertebral artery is the first and largest branch of the subclavian artery. It supplies the spinal cord and the brain. It ascends in the interval between the anterior scalene anterior and longus colli muscles, entering the foramen in the transverse process of the sixth cervical vertebra, just below the level of the lower border of the cricoid cartilage. It continues upward through the foramina to the transverse processes of the remaining cervical vertebrae to the skull. After passing through the foramen in the transverse process of the axis, it takes an S-shaped course upward and lateral. It then passes through the foramen in the transverse process of the atlas, curving backward behind the articular process in a deep groove on the superior surface of the posterior arch of the atlas. Here it lies in the suboccipital triangle, and pierces the posterior ligaments of the occipito atloid and the dura mater of the spinal cord. It enters the foramen magnum and becomes intracranial. It unites with the vertebral artery of the opposite side near the lower border of the pons to form the basilar. The branches of the vertebral artery consist of two sets: cervical branches given off in the neck and cranial branches given off within the cranium. The branches given off in the neck are the lateral spinal and the muscular. The lateral spinal arteries pass through the intervertebral foramina and each divides into two branches for the supply of the spinal cord, its membranes, and the bodies of the vertebrae. The muscular branches are given of immediately before the vertebral artery pierces the posterior ligament of the occipito-atloid. They supply the deep muscles of the neck. They anastomose with the occipital and the ascending and deep cervical arteries.

Arteria vertebralis

Artère vertébrale