Part 72

The trunks of the vena jugularis or vena cephalica communis pass subcutaneously on both sides near the trachea and the esophagus. Near the height of the thyroid gland they almost touch the carotid artery. They then cross, dorsalward, the trunk of the subclavian artery, and in their course receive the vertebral vein and unite with the subclavian vein toward the side of the vena brachiocephalica. The union on the right side lies to the right of the anterior aorta, and the union on the left side lies to the left of the pulmonary artery.

The jugular vein (Fig. 18, No. 4) receives in its course the following veins:

The =venæ linguales= (Fig. 62, No. B, 7), which at times empty into the vena cephalica posterior.

The =vena occipito-collares=, which arises on the ventral side from the muscles of the neck and the vertebræ; empties into the vena occipitalis lateralis and also communicates with the vena jugularis by anastomoses.

The =venæ ascendentes laterales=, which collect blood from the lateral sides of the neck.

The =venæ colli cutineæ=, which enter the jugular vein laterally. The upper branches are directed crosswise, and are shorter than the lower ones. The lower branches are located near the thorax, are directed upward, and anastomose by fine terminal twigs. Plexuses are frequently formed in the inner side of the skin of the neck.

BRANCHES OF THE VENA SUBCLAVIA

( Vena profunda ulnaris ( Vena brachialis ( Vena profunda radialis ( Truncus venæ ( ( Vena profunda humeri ( axillaris ( ( ( Vena basilica or cutinea ulnaris ( ( ( Vena cutinea abdomino-pectoralis Truncus venæ ( Vena pectoris ( Vena infrascapularis anterior subclaviæ ( externa ( Vena thoracica externa ( Vena coracoidea ( Vena sternalis

The =venæ esophageæ= are numerous smaller veins formed in closely woven plexuses in the region of the esophagus along the neck. Some pass upward and some downward.

The =venæ tracheales= are located on the supero-lateral side of the trachea and along the edge of the lateral tracheal muscle. They have numerous anastomoses transversely with the longitudinal vein of the cervical region, anteriorly with the vena lingualis, and on the left side with the left jugular vein.

The =vena subscapularis= passes along the median line of the scapula to the side of the jugular vein, and anastomoses with the vertebral vein.

The =venæ glandularum thyroidearum= are several small, short veins coming from the thyroid gland.

The =vena vertebralis=, originating near the atlas, is a continuation of the internal occipital vein. The internal occipital vein receives the bulk of the blood from the brain and communicates with the lateral veins of the cervical region and collects blood from the cervical vertebra. The vertebral vein accompanies the vertebral artery and the deep sympathetic nerve trunk in the vertebral canal. The vein either leaves this canal with the vertebral artery at a point near the last two vertebral nerve trunks of the brachial plexus, or it leaves the canal one vertebra in front of the vertebral artery.

THE VEINS OF THE DORSAL REGION

The =vena vertebralis lateralis dorsalis= collects blood from the cervical vertebræ, from the dorsal vertebræ, and from the intercostal region.

The blood from the neural canal, including the spinal cord, is collected in one long vein extending from the head to the tail on the upper side of the cord. This vein has sinus-like expansions. Between each two vertebræ it anastomoses with the vertebral vein on each side. In the lumbo-sacral region these anastomotic branches empty into the hypogastric veins.

The =vena intercostalis= is formed in the costal region and anastomoses with the vein extending longitudinally between the capitulum and the tuberculum of the rib.

The =vena vertebralis posterior= at the height of the first and the second dorsal vertebræ, empties into the main trunk of the vertebral vein. Its lower roots come out near the side of the kidney, and unite, forming a large ascending trunk uniting with the vena vertebralis anterior forming one large trunk, which extends into the chest cavity.

The posterior vertebral vein also receives a large vein from the skin of the outer tarsal region and a few vessels from the muscles of the outer abdominal and the outer costal region, from the skin, from the pectoralis muscles, and from the shoulder region.

VEINS OF THE THORAX

BRANCHES OF THE VENA SUBCLAVIA

The =vena thoracica externa= (Fig. 73, No. 2) is made up of veins mainly from the pectoral group of muscles. The posterior branch anastomoses with the vena cutinea. Its anterior branch is made up mainly of branches from the furcular region. It empties into the vena pectoralis externa and the vena pectoralis externa empties into the vena subclavia.

The =vena coracoidea= comes out of the region of the shoulder-joint, passes downward along the inner surface of the coracoid, and receives small branches from the walls of the arteria brachia cephalica and from the pericardium.

The =vena sternalis= (Fig. 73, No. 1) is made up of two branches. The outer branch comes from the muscles of the subclavian region passes over the cristi sterni, medially, to the sterno-coracoid joint and into the breast cavity, where it receives the inner branch, which drains the inner surface of the breast-bone.

The =vena thoracica interna= empties into the vena cava anterior. It extends from the abdominal muscles where it communicates with the epigastric vein. It then passes on the inner side of the thoracic cavity close to the breast-bone and receives many intercostal veins.

The =vena cava sinistra= receives first, the vena proventricularis communis, which collects the blood from the walls of the proventriculus, and second, the vena coronaria cardis magna. This latter vein originates close to the apex of the heart and collects blood principally from the walls of the left ventricle. It connects in the left sulcus transversus with the vena cardis superior and ends at the base of the left upper vena cava. Its exit is not guarded by a valve. The veins of the right ventricle are partly on the surface. They collect blood along the sulcus transversus dexter and enter directly into the right ventricle. The veins of the front part of the heart are small. They collect behind the sulcus coronalis and end either directly into the right auricle or into the vena cardis magna.

VEINS OF THE FORE LIMB

The =vena radialis profunda= accompanies the radial artery on the dorsal anterior rim of the index-finger and passes, on the dorsal side, over the carpal region. It passes through the interosseous ligament between the ulna and the radius, and reaches the ventral surface of the arm. At this point it passes upward and anastomoses with the vena ulnaris. It collects the blood from the skin of the anterior wing region and the flexor muscles of the anterior arm. It empties into the vena brachialis.