The fourth, fifth, sixth, and seventh Pairs proceed from between the Vertebra's, as before, but their Fibres are lost in the Neck of the Omoplata, in the Arm, and in the Diaphragme or Midriff. Here it ought to be observ'd by the way that the Arms receive Branches not only from the
four last Pairs of the Nerves of the Neck, but also from the two first Pairs of the Back, which are extended even to the end of the Fingers: Whence it happens that in the Palsie of the Arms, Remedies are usually apply'd to the Vertebra's of the Neck; and that in Phlebotomy or letting Blood, care must be taken to avoid pricking the Nerve, which accompanies the Basilick Vein in the Elbow.
The twelve Pairs of Nerves that have their Beginning from between the Vertebra's of the Back, are each of them divided into two Branches, as the others; and their Branches are distributed in like manner to the Muscles of the Breast, and to those of the Back and Abdomen.
The five Pairs which take their Rise from between the Vertebra's of the Loins, have thicker Branches than the others, and the distribution of them is made to the Muscles of the Loins, Hypogastrium, and Thighs.
Of the six Pairs of Nerves that proceed from the Os Sacrum, the four Upper with the three Lower of the Loins, send forth Fibres of Nerves to the Thigh, Leg, and Foot; and the two last Pairs impart Nerves to the Anus, Bladder, and privy Parts.
What is the Structure of the Arteries?
The Arteries are long and round Canals, consisting of four sorts of Tunicks or Membranes, which have their Rise from the left Ventricle of the Heart, from whence they receive the Blood, and convey it to all the Parts of the Body for their Nourishment.
What is the Construction of these four Tunicks or Membranes of the Arteries?
The first being thin and Nervous in its outward Superficies, is in the Inside a Plexus or Interlacement of small Veins and Arteries, and Fibres of Nerves, which enter into the other following Tunicks, to nourish them.