The lateral anatomic region of the neck adjacent to the cervical spine contains, among its muscular elements, the cervical plexus and brachial plexus. Nerve plexuses are axon exchange networks that allow peripheral nerves to form from the fibers of two or more consecutive spinal nerves. In this sense, deep to the upper half of the sternocleidomastoid muscle, the spinal nerves from C1 to C4 exchange the axons of their anterior rami in the cervical plexus, giving rise to the peripheral nerves distributed in the anterolateral region of the neck.