| OCR Text |
Show 546 MESSRS. BEDDARD AND MITCHELL ON THE [June 19, Extensor metacarpi radialis.-This has two heads, and the outer of these is tendinous and is connected with the tendon of the patagium. The inner head is fleshy, but is covered with fascia on the side turned towards the radius. The tendons from the two heads remain separate to about half an inch from the common insertion at the base of the metacarpal spine ; but the two tendons are wrapped together by fascia. Ectepicondylo-radialis.-This is a strong muscle arising from the outer condyle of the humerus, where it is covered by a ligament passing from the outer condyle to the ulna. Its flat tendon of origin is in common with that of the extensor digitorum communis. It passes over to be inserted fleshy on to the second eighth of the proximal surface of the radius. Ectepicondylo-ulnaris.-This is a stronger muscle than the last. It arises tendinously from the outer condyle to the humerus, and passing over to the ulna is inserted fleshy to the first third of its radial face. Extensor metacarpi ulnaris.--This arises from the outer condyle of the humerus, its tendon being immediately external to that of the foregoing. It is also connected by a strong band of fascia with the proximal end of the ulna. It is inserted just above the junction of the second and third metacarpals. Extensor digitorum communis.-The tendon of this arises from the external condyle of the humerus. Its slender belly extends a quarter of the length of the ulna, but it receives no fibres from the ulna. After passing over a groove in the distal end of the ulna its tendon forks, a short branch going to the phalanx of the thumb, and a long branch to the base of the first phalanx of the second digit. Extensor longus pollicis.-This arises fleshy from four inches after the first of the shaft of the radius and from the third proximal inch of the ulua. The tendons from the two heads fuse about half an inch from their common insertion to the tendon of the extensor radialis metacarpi. Extensor indicus longus.-Of the two heads of this the first arises fleshy from the third quarter of the radius. The second is much smaller and arises from the ligaments binding the radial carpal to the distal ends of the radius and ulna. The insertion is to the second phalanx of the index at its base, but it sends a broad ligament to the base of the first phalanx. Pronator sublimis.-This arises proximal to the inner condyle of the humerus, and its fleshy insertion is at the end of the first third of the radius. Pronator profundus.-This has exactly the same length as the sublimis. It arises from the inner condyle of the humerus, and its tendon of origin sends a slip to the flexors. It is inserted fleshy on to the radius and on to fascia covering the sublimis. Brachialis inferior.-This flat entirely fleshy muscle arises from the distal end of the humerus, passes over the radius to be inserted for an inch after the first half inch of the ulna. |
