The Vena Cava is immediately divided into two thick Branches, one whereof ariseth upward to the Right Ventricle of the Heart, and forms the ascending Vena Cava; as the other goes downward to the Feet, and constitutes the descending.
What is the Distribution of the ascending Vena Cava?
It perforates the Diaphragm, goes to the Heart, and ascends from thence to the Clavicles,
after having communicated to the Midriff in passing, a small Branch call'd the Phrenicus; as also one or two to the Heart, nam'd the Coronary; and some others to the upper Ribs, besides the single Branch, term'd Azygos, only on the right side. But the Trunk of the ascending Vena Cava, being once come up to the Clavicles, is divided into two Branches, well known by the Name of the Subclavian, one whereof Shoots forth toward the Right side, and the other toward the Left; and they both make various Ramifications like to those of the thick ascending Artery, by producing the Cervicalis or Soporalis, and the Internal and External Jugulars that go to the Head; as also the Axillars, which pass to the Arms and Shoulders, forming the Cephalick, the Median, and the Basilick on the inside of the Elbow.
The descending Vena Cava in like manner accompanieth the Ramifications of the Aorta, or thick descending Artery, to the fourth Vertebra of the Loins, where it sends forth two Branches, nam'd the Iliack, one whereof goes to the Right side, and the other to the Left, both inwardly and outwardly; imparting divers Twigs or lesser Branches to all the Parts contain'd in the Abdomen or lower Belly, even as far as the Fundament, where it makes the External Hæmorrhoidal Veins. Afterward the outward Branch of the Iliack descends in the Thigh, to form the Crural, and others, as far as the Saphæna, together with those that are situated at the end of the Feet.
C H A P XII.
Of the Anatomy of the Abdomen, or lower Belly.
What is the clearest Division of the Human Body into various Parts, and that which is most followed in the Anatomical Schools?