Veins are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal circulations which carry oxygenated blood to the heart. In the systemic circulation, arteries carry oxygenated blood away from the heart, and veins return deoxygenated blood to the heart, in the deep veins.
The left and right brachiocephalic veins are major veins in the upper chest, formed by the union of the ipsilateral internal jugular vein and subclavian vein behind the sternoclavicular joint. The left brachiocephalic vein is more than twice the length of the right brachiocephalic vein.
The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the fifth lumbar vertebra.
In human anatomy, the thoracic duct is the larger of the two lymph ducts of the lymphatic system. The thoracic duct usually begins from the upper aspect of the cisterna chyli, passing out of the abdomen through the aortic hiatus into first the posterior mediastinum and then the superior mediastinum, extending as high up as the root of the neck before descending to drain into the systemic (blood) circulation at the venous angle.
The pterygoid plexus is a fine venous plexus upon and within the lateral pterygoid muscle. It drains by a short maxillary vein.
The superficial temporal vein is a vein of the side of the head which collects venous blood from the region of the temple. It arises from an anastomosing venous plexus on the side and vertex of the head. The superficial temporal vein terminates within the substance of the parotid gland by uniting with the maxillary vein to form the retromandibular vein.
The deep cervical vein is the vena comitans of the deep cervical artery. The vein is formed in the suboccipital region by the convergence of communicating branches of the occipital vein, veins draining the suboccipital muscles, and veins from the venous plexuses that surround cervical nerves. The vein and corresponding artery then pass in between the semispinalis capitis muscle and the semispinalis colli muscle. The vein passes anterior-ward in between the transverse process of the 7th cervical vertebra and the neck of the first rib to terminate in the vertebral vein.
The rectal venous plexus is the venous plexus surrounding the rectum. It consists of an internal and an external rectal plexus. It is drained by the superior, middle, and inferior rectal veins. It forms a portosystemic (portocaval) anastomosis. This allows rectally administered medications to bypass first pass metabolism.
The lumbar veins are four pairs of veins running along the inside of the posterior abdominal wall, and drain venous blood from parts of the abdominal wall. Each lumbar vein accompanies a single lumbar artery. The lower two pairs of lumbar veins all drain directly into the inferior vena cava, whereas the fate of the upper two pairs is more variable.
The external vertebral venous plexuses consist of anterior and posterior plexuses which anastomose freely with each other. They are most prominent in the cervical region where they form anastomoses with the vertebral, occipital, and deep cervical veins.
The internal vertebral venous plexuses lie within the vertebral canal in the epidural space, embedded within epidural fat. They receive tributaries from bones, red bone marrow, and spinal cord. They are arranged into four interconnected, vertically oriented vessels - two situated anteriorly, and two posteriorly:
The basivertebral veins are large, tortuous veins of the trabecular bone of vertebral bodies that drain into the internal and external vertebral venous plexuses.
The intervertebral veins accompany the spinal nerves through the intervertebral foramina to drain the internal vertebral venous plexuses into the external vertebral venous plexuses. They drain into vertebral vein, intercostal veins, lumbar veins, and lateral sacral veins. Upper posterior intercostal veins may additionally drain via brachiocephalic vens. They may drain to ascending lumbar veins. They may drain into the inferior vena cava directly, reaching it by winding around the surface of the vertebral body.
In human male anatomy, the dorsal veins of the penis are blood vessels that drain the shaft, the skin and the glans of the human penis. They are typically located in the midline on the dorsal aspect of the penis and they comprise the superficial dorsal veinof the penis, that lies in the subcutaneous tissue of the shaft, and the deep dorsal veinof the penis, that lies beneath the deep fascia.
The pampiniform plexus is a venous plexus – a network of many small veins found in the human male spermatic cord, and the suspensory ligament of the ovary. In the male, it is formed by the union of multiple testicular veins from the back of the testis and tributaries from the epididymis.
The vesical venous plexus is a venous plexus situated at the fundus of the urinary bladder. It collects venous blood from the urinary bladder in both sexes, from the accessory sex glands in males, and from the corpora cavernosa of clitoris in females. It drains into the internal iliac veins via several vesical veins.
In vertebrates, a venous plexus is a normal congregation anywhere in the body of multiple veins.
The prevertebral fascia is the layer of deep cervical fascia that surrounds the vertebral column. It is the deepest layer of deep cervical fascia.
Anterior spinal veins are veins that receive blood from the anterior spinal cord.
The cerebrospinal venous system (CSVS) consists of the interconnected venous systems of the brain and the spine.
