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Show 418 MR. A. S A N D E R S O N T H E [June 9, of the humerus and from the whole length of the ulna, and is inserted into the pisiform bone. Flexor sublimis digitorum arises from the strong tendinous arch, one end of which is attached to the pisiform bone and the other to the scaphoid, and from the palmar fascia ; it immediately divides into five muscular slips, each of which is attached to a tendon of the flexor profundus and to the head of the metacarpal bone of its respective digit; although this is not perforated by the long tendon, it represents the perforatus, as it will be seen, when we come to the foot, that the corresponding muscle there allows the long tendon to pass between its two heads. Flexor profundus digitorum arises from the middle portion of the inner condyle of the humerus and from the lower two-thirds of the ulna; passing beneath the annular ligament, it becomes developed into a broad expansion, which, in the palm, divides into four long tendons, going to the terminal phalanx of the pollex, second, third, and fourth digits. The fifth digit has a long tendon to itself, which is given off high up in the forearm. Pronator cquadratus arises from the whole length of the ulna, and is inserted into the distal half of the radius, occupying the place of the interosseous membrane. Flexor accessorius digitorum.-There are four muscular slips which may he thus called ; two of them arise from the tendinous expansion of the long flexor, and, forming very fine tendons, are inserted into the last phalanx but two of the third and fourth digits respectively. Two other slips arise from the bone of the carpus which appears to represent the cuneiform, and from others, in the first row ; one of these joining the long tendon, developes, in addition, a tendon of its own, which is inserted into the penultimate phalanx of the second digit; it has also a muscular insertion into the base of the first phalanx of the same digit; the other slip is simply attached to the long tendon going to the pollex, without having one of its own. Lumbricales.-There are five muscles which correspond to the lumbricales-viz. one on each side of the fourth, one on each side of the third, and one on the ulnar side of the second digit. Abductor quinti digiti arises from the pisiform bone, and is inserted into the whole length of the ulnar edge of the metacarpal bone of the fifth digit. Abductor poliicis arises from scaphoid, and is inserted into the whole length of metacarpal bone of pollex. Beneath these there are five palmar interossei, which radiate from the first row of bones of carpus, and are inserted into the heads of the metacarpal bones of their respective digits, one for each. Supinator longus arises from the lower third of the outer edge of tbe humerus, above the condyle, and is inserted into the distal two-thirds of the radius. Supinator brevis arises from the outer condyle distad of the last, and is inserted into nearly the whole length of the radius. Extensor carpi radialis arises from the outer condyle of the humerus next to the last muscle, and, forming a long slender tendon, |
