CHAP. III. Of the Nerves which proceed from the spinal Marrow, and first of the Nerves ari∣sing from the Neck, and so of the Nerves of the whole Arm.
ANd so much for those ten pare of Nerves, which proceed from the Medulla oblongata within the skul: the other pares do now follow, which are thirty in number, somtimes nine and twenty, from the same begin∣ning, viz. the Medulla oblongata being passed out of the Skull into the Back-bone: where it is termed Medulla▪ spinalis or Dorsalis, the Marrow of the Back. Now the little Nerves proceed out of the holes of the Back-bone, in a continued course bending themselves inward, from the uppermost to the lowermost.
Out of the Marrow, while it is in the Neck, there arise seven pare of Nerves as some reckon, eight pare as others count, disseminated into the whole outward Head and the neighbouring Muscles.
The first and second pare have this peculiar above all the rest, that they proceed not from the sides, but from the fore and hinder part, by reason of the peculiar Articulation of the first and second Vertebra.
Now the first pare arises between the hinder-part of the Head and the first Vertebra. Joh. Leonicenus of Padua, a dextrous Anatomist in taking out of the Nerves, denied that there was any such pare as this, because he could neither see it, nor can •••• come out of the first Vertebra ha∣ving no hole, and sticking closely to the second Vertebra and the Occiput.
The second pare arises between the first and second Ver∣tebra, and so of the rest in order.
The first and second pare are disseminated into the Mus∣cles of the Head, and to the Ears.
The third and fourth into the Muscles of the Cheeks, also those which are common to the Head and Neck.
The fift with the branches of the fourth and sixt, do make the remarkable midrif Nerves: and the fift with the foresaid, sends a part backwards, and a part forward into the Muscles bowing the Head; those of the Arms, Shoulderblades, and the Skin there.
The sixt to the Arms and the hollow of the Shoulder∣blades.
The seventh is joyned with two of its Neighbours, viz. the sixt of the Neck and first of the Chest, whose greatest part goes to the Arms and as far as the Hands.
For there are carried into the Arms five or six pare of Nerves, viz. from the fift, sixt, and seventh pares of the Neck, also from the first and second pares of the Chest. which when they first break forth, they are all mix∣ed and united, nor are separated without dammage, and soon after they are severally divided into the foresaid Pares; to the End haply, that by that light concourse, a collection might be made of animal spirits. Hence To∣pick Medicaments, in a Palsie, or Convulsion of the Arm, the upper part of the Arm being affected must be applied on the side of the upper part of the Back and the Neck, from whence the Nerves proceed, not directly in the middle, either of the Back or Neck, unless by reason of the common beginning of the Nerves.
The first Pare, from the fift pare of the* 1.1 Neck, goes chiefly into the Deltoides Mus∣cle, and the Skin of the Arm, leaving a part which accompanies the Vena humeraria.
The second being thicker, is carried through the Middle and Forepart of the Cubit, where it furnishes the Muscu∣lus biceps, whereupon it is joyned with the third Nerve, and afterwards going downwards, it salutes the Supinator longior with a twig: but at the bending of the Cubit, it is divided somtimes into Two, otherwhites into three branches.
- 1. The upper and lesser, goes along the outside of the Arm, to the outer part of the first or second Interjuncture of the Thumb.
- 2. The middle and thicker descends obliquely within the Cubit to the Wrist.
- 3. The lower, being stretched along by the inner branch of the Basilica, is spent into the Skin of the Cubit and Hand.
The third is joyned with the former, under the Muscle Biceps, it provides for the Brachiaeus and the inside of the Hand.
The fourth being the thickest, goes along with the Ve∣na profunda and the Artery, Afterwards is variously divi∣ded. Now it furnishes the Muscles which extend the Cu∣bit, the Wrist, the Thumb, the fore and the middle Fin∣ger, and the Muscles which stretch the Fingers out.
The fift stretcht along by the former, between the Mus∣cles of the Cubit, which it furnishes descending through the lower and hinder part of the Cubit (where when we strike against any thing or compress the Nerve, we feel a nummedness in our fingers) in the middle thereof it is divided into two.
One branch goes externally through the Ulna to the Middle Finger, Ring-finger, and little Finger. On the Inside of the Fingers for securities sake, that they may give place in laying hold of any thing, for there Wounds are more pernicious than in the middle.
The other goes inwardly through the Ulna betwixt the Finger-bending Muscles as far as the Wrist, and sends branches to the same parts as the former sent to.
The sixt is spent into the Skin of the Cubit, going be∣twixt the Skin and the Membrane.