points of practical interest about these muscles are noticed in the article ANATOMY (Supegieial and -Artistic). In addition to these the brachio-radialis is a exor of the forearm, though it arises from the outer supracondylar ridge of the humerus. It is su plied by the musculo-spiral nerve, the Hexor carpi ulnaris by the ulinar, the rest b the median. The deep muscles of the front of the forearm consist oi' the flexor longus pollieis running from the radius to the terminal phalanx of the thumb, the jtexor profundus dtgitorum from the ulna to the terminal phalanges of the Fingers, and the pronator quadratus From A. M. Paterson. Cunningham's Text Book of AMW”-W

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F'°m A~ M- Paterson, Cunninghame Text Book of Anatomy.

FIG. 7.-Superficial Muscles on the Front of the Arm and Forearm.

passing across from the lower third of the ulna to the same amount of the radius. These three muscles are supplied by the anterior interosseous branch of the median nerve, but the flexor profundus digitorum has an extra twig from the ulnar. The extensor muscles at the back of the forearm are also divided into superficial and deep sets (see fig. 8). The former rise from the region of the external condyle of the humerus, and consist of the extensor carpi radialfis longwf and brevior inserted into the index and medius metacarpal bones, the extensor communis digitorum to the middle and distal phalanges of the fingers, the extensor minimt digiti, the extensor cargi ulnarfis passing to the metatarsal bone of the minimus, and t e supinator brevis wrapping round the neck of the radius to which it is inserted. The aconeus which runs from the external condyle to the olecranon process is really a part of the triceps. The deep muscles rise from the posterior surfaces of the radius and ulna, and are the extensor ossis metacarpi pollicis, the name of which gives its insertion, the extensor brevis pollicis to the proximal phalanx, and the extensor longus pollicis to the distal phalanx of the thumb, while } TRAPEZIUS Demom Inrnnsrmxrus Trims unjon Lxnssnms DOES! CHIAHS ANTICUS Tnrcz-:rs inter-muscular septum BRACHIO-RADIALIS Ulnar nerve Eximzsor. cnnm x.u>1AL|5 exon Exrmxsor. cum nnnmus BREVIOR fascia of forearm 09 COEMUNIS DIGITORUH CARP! 'ULNARIS Exrnnson ossls ME'rAcA1u>: POLLICKS Exranson nnnvls 1=o1 ucrs Ex'rn1~:sor rmmn morn Timmons or Exrensoas or cnarvs Posterior annular ligament Exrnnsox mucus rotucrs Exhansor mmcxs FIG. 8.—The Muscles on the Back of the Arm; Forearm and Hand. the extensor 'indicfis joins the extensor communis slip to the, index linger; all these posterior muscles are supplied by the posterior interosseous nerve. In front and behind the wrist the tendons are bound down by the anterior and posterior annular ligaments, while on the flexor surface of each linger is a strong fibrous sheath or theca for the flexor tendons. The ball of the thumb is occupied by short muscles called the thenar group, while hypnthenar muscles are found in the ball of the little linger. The four lumbrfical muscles (fig. 9, tl)

run from the Hexor profundus digitorum tendons to those of the