The occipital vein begins as a plexus

Plexus

A plexus is a part of nervous system. Plexus has a slightly different definition in vertebrates and in invertebrates.- In vertebrates :In vertebrates, a plexus is an area where nerves branch and rejoin. The electrical signals do not mix; rather, the fibres travel together with their electrical...

 at the posterior aspect of the scalp from the external occipital protuberance

External occipital protuberance

Near the middle of the occipital squama is the external occipital protuberance, and extending lateralward from it on either side is the superior nuchal line, and above this the faintly marked highest nuchal line.It is less pronounced in females....

 and superior nuchal line to the back part of the vertex

Vertex (anatomy)

In arthropod and vertebrate anatomy, the vertex refers to the upper surface of the head.In humans, the vertex is formed by four bones of the skull: the frontal bone, the two parietal bones, and the occipital bone...

 of the skull

Human skull

The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...

.

From the plexus emerges a single vessel, which pierces the cranial attachment of the Trapezius and, dipping into the venous plexus

Suboccipital venous plexus

The Suboccipital Venous Plexus drains the back of the head.It communicates with the external vertebral venous plexuses. The external vertebral venous plexuses travel inferiorly from this suboccipital region to drain into the brachiocephalic vein...

 of the suboccipital triangle

Suboccipital triangle

The suboccipital triangle is a region of the neck bounded by the following three muscles of the suboccipital group of muscles:* Rectus capitis posterior major - above and medially* Obliquus capitis superior - above and laterally...

, joins the deep cervical

Deep cervical vein

The deep cervical vein accompanies its artery between the Semispinales capitis and colli....

 and vertebral vein

Vertebral vein

The vertebral vein is formed in the suboccipital triangle, from numerous small tributaries which spring from the internal vertebral venous plexuses and issue from the vertebral canal above the posterior arch of the atlas....

s.

Occasionally it follows the course of the occipital artery

Occipital artery

The occipital artery arises from the external carotid artery opposite the facial artery, its path is below the posterior belly of digastric to the occipital region. This artery supplies blood to the back of the scalp and sterno-mastoid muscles...

 and ends in the internal jugular; in other instances, it joins the posterior auricular vein

Posterior auricular vein

The posterior auricular vein begins upon the side of the head, in a plexus which communicates with the tributaries of the occipital vein and superficial temporal veins....

 and through it opens into the external jugular.

The parietal emissary vein connects it with the superior sagittal sinus

Superior sagittal sinus

The superior sagittal sinus , within the human head, is an unpaired area along the attached margin of falx cerebri. It allows blood to drain from the lateral aspects of anterior cerebral hemispheres to the confluence of sinuses...

; and as it passes across the mastoid portion of the temporal bone

Temporal bone

The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebrum.The temporal bone supports that part of the face known as the temple.-Parts:The temporal bone consists of four parts:* Squama temporalis...

, it receives the mastoid emissary vein which connects it with the transverse sinus.

The occipital diploic vein sometimes joins it.