. Medical and surgical therapy. cond phalanx on thefirst, the third phalanx remaining extended : the flexor profundusdigitorum flexes the second and third phalanges on the Theiraction on the first is very weak or nil. The synergic action of the extensors of the hand and Angers 54 CLINICAL FORMS OF NERVE LESIONS increases the power of the flexors. Complete flexion of the fingers,as in the action of clutching, is only ])ossible when the extensorsare contracted to the fullest extent. The flexor longus poUicis only flexes the last phalanx of the thumb. The first and second lumbricales act
. Medical and surgical therapy. cond phalanx on thefirst, the third phalanx remaining extended : the flexor profundusdigitorum flexes the second and third phalanges on the Theiraction on the first is very weak or nil. The synergic action of the extensors of the hand and Angers 54 CLINICAL FORMS OF NERVE LESIONS increases the power of the flexors. Complete flexion of the fingers,as in the action of clutching, is only ])ossible when the extensorsare contracted to the fullest extent. The flexor longus poUicis only flexes the last phalanx of the thumb. The first and second lumbricales act like the interossei into whichthey are inserted ; they cause flexion of the first phalanges andextension of the second and third. The lumbricales do not assist in lateral movement, with theexception of the first, which abducts the first phalanx of the indexfinger slightly. The muscles of the thenar eminence have been divided by Duchenne Abductor longuspollicis. Opponens. Abductor brevispollicis. Flexor brevispollicis. Flexor carpiulnaris. Abductor minimidigiti. Flexor brevisminimi digiti. Fig. 19.—Muscles of the hand. (of Boulogne) into two groups: (1) Those which are inserted intothe outer side of the first phalanx of the thumb (abductor pollicisand the outer head of the flexor brevis pollicis); and (2) thosewhich are inserted into the internal sesamoid on the inner side ofthe first phalanx of the thumb (adductor transversus and innerhead of the flexor brevis pollicis) (fig. 19). The opponens pollicis should be considered separately. It flexesthe first metacarpal sharply on to the wrist and draws it inwardat the same time. The abductor pollicis and the outer head of flexor brevis pollicis givethe first metacarpal a movement similar to that made by theopponens pollicis ; but they simultaneously extend the second THE MEDIAN NERVE 55 phalanx and bend the first on its outer side, making it revolve fromwithout inwards on its axis, so that the tip of the thumb is oppose
Size: 1404px × 1781px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpub, booksubjecttherapeutics
