These arteries collectively form a ring of blood vessels known as the Circle of Willis. At the base of the brain several communicating arteries form anastomoses, or passages, between the left and right posterior cerebral, left and right internal carotid, and left and right anterior cerebral arteries. Although the external and internal jugular veins are separate vessels, there are anastomoses between them close to the thoracic region. It ends in the subclavian vein. This is the smaller of the two vessels that drain blood from the head and neck into the subclavian.
In the neck and head exterior to the skull, the external carotid artery provides blood flow to the skin, muscles, and organs. Blood from the more superficial portions of the head, scalp, and cranial regions, including the temporal vein and maxillary vein , flow into each external jugular vein. The human brain is so powerful and metabolically active that it uses about 20% of all of the oxygen and glucose taken in by the body each day. The facial vein is connected to the cavernous sinus by the superior ophthalmic vein , or its supraorbital tributary, or by the deep facial vein to the pterygoid plexus, and, hence, to the cavernous sinus. It descends superficially, covered by the platysma, superficial fascia, and skin.
The supratrochlear veins diverge laterally and form the facial vein near the medial canthus. The hypoglossal nerve has been displaced downward in this preparation. From near its termination a communicating branch often runs down the anterior border of the Sternocleidomastoideus to join the lower part of the anterior jugular vein. It also includes the veins that return deoxygenated blood from these organs to the heart. It receives the superior laryngeal and cricothyroid veins.
Sometimes the first intercostal vein opens in the vertebral vein. The middle temporal vein receives the orbital vein, which is formed by some lateral palpebral branches, and passes backward between the layers of the temporal fascia to join the superficial temporal vein. The Superior Thyroid Vein v. The anterior jugular vein v. This plexus ends in a single trunk, which emerges from the foramen transversarium of the sixth cervical vertebra, and opens at the root of the neck into the back part of the innominate vein near its origin, its mouth being guarded by a pair of valves.
The vertebral vein is formed from numerous small tributaries from the internal vertebral plexuses, which arise from the vertebral canal above the posterior arch of the atlas. From this net-work frontal and parietal branches arise, and unite above the zygomatic arch to form the trunk of the vein, which is joined in this situation by the middle temporal vein, from the substance of the Temporalis. The facial vein joins the internal jugular vein near the greater horn of the hyoid bone. The left vein is generally smaller than the right, and each contains a pair of valves, which are placed about 2. The Circle of Willis provides insurance that the brain will continue to receive blood flow in the event that one of its major arteries is blocked by allowing blood flow between all of the major arteries to all of the regions of the brain. The superficial temporal vein receives in its course some parotid veins, articular veins from the temporomandibular joint, anterior auricular veins from the auricula, and the transverse facial from the side of the face.
This sinus receives blood from the superior and inferior ophthalmic veins, the middle superficial cerebral veins, and from another dural venous sinus; the sphenoparietal sinus. Copyright © 2009, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences. The vein receives tributaries from the auricle and stylomastoid vein. It runs downwards and forwards deep to the infrahyoid muscles to the upper pole of thyroid gland. The two veins are joined, at the root of the nose, by a transverse branch, called the nasal arch, which receives some small veins from the dorsum of the nose.
It descends obliquely near the side of the nose also called angular vein at this level , turning posterolateral under the orbit, passing downwards and backwards behind the facial artery, until it reaches the mandible angle, where it is joined by the retromandibular 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. Several major arteries - including the facial, superficial temporal, and occipital arteries - branch off from the external carotid to provide blood to the many superficial structures of the head. It has a path of descent behind the auricle and joins the posterior division of the retromandibular vein. Both veins may be replaced by a midline trunk. The initial part of the internal jugular vein is dilated and is known as the superior bulb.
The Veins of the Exterior of the Head and FaceThe veins of the exterior of the head and face are: Frontal. Air will be drawn into the vein, producing cyanosis, and can stop blood flow through the right atrium. This vein receives in its course the inferior petrosal sinus, the common facial, lingual, pharyngeal, superior and middle thyroid veins, and sometimes the occipital. Clinical Relevance: Severance of the External Jugular Vein The external jugular vein has a relatively superficial course down the neck, leaving it vulnerable to damage. Occasionally the frontal veins join to form a single trunk, which bifurcates at the root of the nose into the two angular veins.
They occasionally open into the facial, lingual, or superior thyroid vein. The vena comitans of the hypoglossal nerve ranine vein , a branch of considerable size, begins below the tip of the tongue, and may join the lingual; generally, however, it passes backward on the Hyoglossus, and joins the common facial. The veins draining the cervical vertebrae and the posterior surface of the skull, including some blood from the occipital sinus, flow into the vertebral veins. These veins drain blood from the anterior face, trachea, , , larynx, and. The plexus connects with the facial vein through the deep facial vein and with the cavernous sinus through the sphenoidal emissary foramen, foramen ovale, and foramen lacerum , ,. The deep lingual vein begins at the tip of the tongue and runs posteriorly along the inferior surface of the tongue.