The diploic veins are found in 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...

, and drain the diploic space. This is found in the bone

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

s of the vault of the skull, and is the marrow

Bone marrow

Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...

-containing area of cancellous bone between the inner and outer layers of compact bone.

The diploic veins drain this area into the dural venous sinuses

Dural venous sinuses

The dural venous sinuses are venous channels found between layers of dura mater in the brain...

.

Specific diploic veins

They are usually four in number: one frontal, two temporal, and one occipital.

• (1) the frontal, which opens into the supraorbital vein
  Supraorbital vein
  The supraorbital vein begins on the forehead where it communicates with the frontal branch of the superficial temporal vein.It runs downward superficial to the Frontalis muscle, and joins the frontal vein at the medial angle of the orbit to form the angular vein.Previous to its junction with the...
  
   and 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...
  
  .

• (2) the anterior temporal, which is confined chiefly to the frontal bone
  Frontal bone
  The frontal bone is a bone in the human skull that resembles a cockleshell in form, and consists of two portions:* a vertical portion, the squama frontalis, corresponding with the region of the forehead....
  
  , and opens into the sphenoparietal sinus
  Sphenoparietal sinus
  The cavernous sinus receives the superior ophthalmic vein through the superior orbital fissure, some of the cerebral veins, and also the small sphenoparietal sinus, which courses along the under surface of the small wing of the sphenoid....
  
   and into one of the deep temporal veins, through an aperture in the great wing of the sphenoid.

• (3) the posterior temporal, which is situated in the parietal bone
  Parietal bone
  The parietal bones are bones in the human skull which, when joined together, form the sides and roof of the cranium. Each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin pariet-, wall....
  
  , and ends in the transverse sinus, through an aperture at the mastoid angle of the parietal bone
  Parietal bone
  The parietal bones are bones in the human skull which, when joined together, form the sides and roof of the cranium. Each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin pariet-, wall....
  
   or through the mastoid foramen
  Mastoid foramen
  The mastoid foramen is a large hole in the posterior border of the temporal bone. It transmits a Mastoid emissary vein to the sigmoid sinus and a small branch of the occipital artery, the posterior meningeal artery to the dura mater.-Variations:...
  
  .

• (4) the occipital, the largest of the four, which is confined to the occipital bone
  Occipital bone
  The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoidal in shape and curved on itself...
  
  , and opens either externally into the occipital vein
  Occipital vein
  The occipital vein begins as a plexus at the posterior aspect of the scalp from the external occipital protuberance and superior nuchal line to the back part of the vertex of the skull....
  
  , or internally into the transverse sinus or into the confluence of the sinuses (torcular Herophili).