The Cubitæus Externus taking its rise from the hinder-part of the Elbow, passeth under the Annular Ligament, and adheres to the upper and outward-part of the Bone of the Metacarpus that stayeth the little Finger.
The Radiæus Externus, or the Longus, having its Origine in the edge of the lower part of the Arm-Bone, slides from thence along the Radius on the outside, extends it self under the Annular Ligament, and cleaves to the Wrist-Bone, which stayeth the Fore-Finger.
The Brevis or short Muscle of the Wrist springs from the lower part of the same Edge; afterwards it runs along the Radius, passeth under the Annular Ligament, and is terminated in the Bone of the Carpus or Wrist, which stayeth the Middle Finger. But we must take notice, that besides these six Muscles, there is also Caro quædam quadrata, or a square piece of Flesh under the Palmaris, which seems to arise from the Thenar, and sticks to the eighth Wrist-Bone. It is supposed that this Musculous piece of Flesh serves with the Hypothenar of the little Finger, to make that which is call'd Diogenes's Cup.
How many Motions are there in the Fingers, and what are their Muscles?
The Fingers are bent, extended, and turn'd from one side to the other by the means of twenty-three Muscles, whereof ten are proper, and thirteen common: The former are those that serve all the Fingers in general, and the other those that are particularly serviceable to some of them: The Common are the Sublimis, the Profundus, the common Extensor, the four Lumbricales, and the six Interossei.
The Sublimis or Perforatus, arising from the internal part of the lower Process of the Humerus or Shoulder-Bone is divided into four Tendons, which run below the Annular Ligament of the Wrist, and are inserted in the second Phalanx of the Bones of the four Fingers, after having stuck in passing to those of the first Phalanx, to help to bend it. It is also observed that every one of these Tendons hath a small cleft in its length, to let in the Tendons of the Profundus.
The Profundus or Perforans lies under the Sublimis, deriving its Original from the top of the Cubitus and Radius. It creeps along these two Bones, and is divided into four Tendons, which pass under the Annular Ligament, and slip into the Fissures of the Tendons of the Sublimis, to adhere to the third Phalanx of the Fingers, which they bend with the Sublimis: So that these two Muscles make together the bending of the Fingers.
The Extensor Magnus is that which extends the four Fingers. It springs from the external and lower Process of the Arm-Bone, and is divided into four flat Tendons, which pass under the Annular Ligament, and cleave