OCR Text |
Show 1884.] ANATOMY OF SCOPUS UMBRETTA. 547 is continued without any change to the radial aponeurosis ; the inner tendon about half way down gives off in front a broad, thin, flat tendon, which passes down parallel to the other half of the tendon and is inserted near to it; at this point it receives the slip from the tendon of the tensor patagii longus already referred to. There is no biceps slip to the patagium. 13. The biceps has the usual double origin, and is inserted on to the radial margin of the ulna and on to the ulnar margin of the radius. 14. The anconeus longus arises from the scapula close to the articulation of the humerus by a single head, the outer half of which is tendinous about half an inch from the origin ; it gives off a broad flat tendon to the outer edge of the humerus ; it ends below in a long stout tendon attached to the anterior border of the olecranon process of the ulna. 15. The triceps arises from the head of the humerus just external to the insertion of the teres and from a considerable proportion of the shaft; it blends with the anconeus longus at its insertion on to the ulna behind the latter. The expansor secundariorum appears to be absent. 16. The pronator radii superficialis arises from the inner condyle of the humerus ; it is inserted into the upper margin of the radius. 17. The pronator radii profundus, twice as large as tbe last, arises from the humerus below it ; it is inserted on to the radius below the insertion of the last, and extends considerably beyond. Between the two pronators is a small muscle which arises in common with the pronator profundus ; it is attached partly to the tendinous surface of the latter and partly by a slender tendon to the radius. 18. The flexor carpi ulnaris is a strong muscle arising by fleshy origin from distal extremity of humerus; it is inserted by a long thick tendon on to the ulnar carpal bone. 19. The external anconeus arises from the common tendon from the external condyle of humerus; it is inserted into the proximal one half of the upper part of the ulna (except at the extreme end). 20. The extensor carpi ulnaris arises from a long tendon from outer condyle of humerus together with the anconeus externus, and from the tendinous septum between it and the latter; it is inserted by a long tendon about one third of the way down the metacarpal of digit II. on the outer inferior margin. 21. The extensores carpi radialis longus and brevis arise from the outer condyle of humerus above all the other muscles of the forearm; they are in close contact for the whole of their length, and are inserted on to the tuberosity of the metacarpal of the first digit. 22. The extensor communis digitorum arises from the outer condyle of the humerus above and a little behind the extensor carpi ulnaris; it divides at the base of the thumb into two tendons, the first of which is attached to the digital margin of the phalanx of the pollex ; the other is similarly attached to the second phalanx of digit n . |